| 1. |
- Johansson, Jakob, et al.
(författare)
-
Screening Environmental Impact Reduction Enabled by Brass Reclamation through Hot Forging Operations
- 2020
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Ingår i: SPS2020 - Proceedings of the Swedish Production Symposium. - 9781614994398 ; 13, s. 241-248
-
Konferensbidrag (refereegranskat)abstract
- The traditional method for recycling brass chips is to send the scrap back to the material manufacturer for re-melting. Alternatively, brass chips can be reclaimed through hot forging operations at the production site. As an initial screening of the environmental impact of this novel reclamation method, the impacts of this new method was compared to conventional brass production (including recycling) for a specific part. These two production routes were compared in terms of cumulative energy demand and climate change impact. The comparison between the two production routes showed that the new reclamation method reduced the cumulative energy demand with 29 % and climate change impact with 30 % for production of a specific part compared to conventional recycling. It is, however, important to note that the material produced using hot forging reclamation method have slightly lower mechanical properties as compared to the traditionally recycled material. Currently the novel recycling method is only tested in lab scale and therefore, further studies are needed in order to fully assess the environmental impacts of the new reclamation method compared to conventional brass production.
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| 2. |
- Bushlya, Volodymyr, et al.
(författare)
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On the Analytical Representation of Chip Area and Tool Geometry when Oblique Turning with Round Tools. Part 1: Chip Area Parameters under Variation of Side and Back Rake Angle
- 2015
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Ingår i: 15th CIRP Conference on Modelling of Machining Operations (15TH CMMO). - : Elsevier BV. - 2212-8271. ; 31, s. 417-422
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Konferensbidrag (refereegranskat)abstract
- Chip area parameters, such as undeformed chip thickness, equivalent chip thickness, contact edge length, etc., along with tool angles are among defining for the mechanical and thermal conditions of the cutting process. This paper considers the case of external turning with a round insert under variation, in wide range, of back and side rake angles and their influence on the main chip area and surface roughness parameters. Influence of other process variables, such as feed, depth-of-cut and nose radius, is also studied. The developed analytical models and algorithms allow, not only to study the fundamental relationships, but to apply them in the design of new tools for conventional and rotary turning.
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| 3. |
- Bushlya, Volodymyr, et al.
(författare)
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On the Analytical Representation of Chip Area and Tool Geometry when Oblique Turning with Round Tools. Part 2: Variation of Tool Geometry along the Edge Line
- 2015
-
Ingår i: 15th CIRP Conference on Modelling of Machining Operations (15TH CMMO). - : Elsevier BV. - 2212-8271. ; 31, s. 423-428
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the models, analytical equations and results of analysis for determination of major cutting edge, orthogonal and normal clearance and rake angles, and cutting edge inclination angle. The analysis is carried for variable side and back rake angles used by the tool manufacturers and a corresponding variation of the geometry along the edge line for the case of round tools. The influence of tool nose radius, chamfer/chipbreaker angle and depth-of-cut was considered as well. Significant variation in orthogonal geometry from that stated in catalogues was found in most cases. The developed analytical solutions and algorithms allow the establishment of fundamental geometrical relationships and giving a correct prediction when developing new tools for conventional and rotary turning. (C) 2015 The Authors. Published by Elsevier B.V.
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| 4. |
- Bushlya, Volodymyr, et al.
(författare)
-
Wear mechanisms of uncoated and coated cemented carbide tools in machining lead-free silicon brass
- 2017
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 376-377, s. 143-151
-
Tidskriftsartikel (refereegranskat)abstract
- Free-machining brass containing 2–3% of lead is a preferred industrial material as it shows excellent machinability where low cutting forces, short chips and reduced tool wear are attained. However this addition of lead, a highly toxic and hazardous material, leads to health and environmental issues. Alternative lead-free brasses are known for poor chip control and accelerated tool wear. The current study focuses on wear mechanisms of uncoated and coated cemented carbide tools when high-speed machining lead-free CuZn21Si3P silicon brass. The study shows that severe crater formation on the rake is the dominant tool failure mode. Microscopy observations indicate the diffusion wear mechanism to be driven by diffusion of cobalt binder into the chips and minor cross-diffusion of copper and zinc. Loss of the binder in cemented carbide is accompanied by adhesive pluck-out of WC grains. As a way to hinder the loss of Co, the diffusion preventing capacity of a-C:H diamond like carbon and (Ti,V,Zr,Nb,Hf,Ta)N nitride coating were tested. SEM, EDX and TEM data show that formation of amorphous SiO2 and stoichiometric β-SiAlON stable layers was observed on the nitride coating, thus preventing diffusional tool wear. O-rich and N-rich glassy amorphous layers in Si-Al-O-N system with ZnS inclusions were found on the DLC coating. Partial delamination of the DLC coating and removal of the glassy phases resulted in localized crater formation associated with diffusional wear.
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| 5. |
- Fallqvist, Mikael, 1982-, et al.
(författare)
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Influence of the tool surface micro topography on the tribological characteristics in metal cutting – Part I Experimental observations of contact conditions
- 2013
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 298, s. 87-98
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of surface micro topography of CVD α-Al2O3 coatings, deposited on cemented carbide inserts, on tribological characteristics in sliding contact and in metal cutting has been investigated using quenched and tempered steel as counter/work material. Pin-on-disc and turning tests were carried out and post-test characterization using 3D optical surface profilometry and scanning electron microscopy was performed in order to investigate the tribological response of the coatings. The results show that surface micro topography can have a significant impact on the tribological performance of Al2O3 coatings under initial and cutting contact conditions. For both kinds of tests the tendency for transfer of workpiece material strongly increases with increasing coating micro topography. In the pin-on-disc tests, a smooth coating surface significantly reduces the friction coefficient. In the turning tests the contact conditions at the flank face increase with decreasing micro topography. In contrast, no general conclusions can be drawn regarding the influence of coating micro topography on the contact conditions at the rake face. The resulting topography of the turned surface was found to increase with increasing coating topography.
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| 6. |
- Hrechuk, Andrii, et al.
(författare)
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Research solution for automatic hole quality analysis when drilling fiber-reinforced composites
- 2023
-
Ingår i: International Journal of Advanced Manufacturing Technology. - 0268-3768. ; 127:7-8, s. 3315-3324
-
Tidskriftsartikel (refereegranskat)abstract
- Fiber-reinforced polymers are highly demanding composites in aerospace and automotive areas because of their excellent mechanical properties such as stiffness and strength-to-weight ratio. The drilling remains the major machining operation applied to composites to provide high-quality holes for joints between parts. Due to composites plied structure, the drilling is accompanied with unusual form metal cutting defects such as delamination and uncut fibers around the drilled hole. Considering that the tool life of some drills reaches over thousands of holes, the research of composites machinability becomes difficult due to demanded labor intensity in manual inspection of the hole quality. Therefore, this paper develops the research solution for automatic analysis of the hole quality in drilled fiber-reinforced materials. The paper proposes a complex of solutions aimed to speed up the analysis of the hole quality when composites drilling. The solution consists of the developed vacuum table, robot arm with high-speed camera, developed top and bottom lightning systems, and Image Processing algorithms for defect detection from captured images. The paper results show how the developed solution can be used for high routine research activities. The output data, including tested 72 cutting data parameters and full-size tool life test, allowed identifying the operational window for high-speed steel drills and the range of tool life, where drill ensures a certain hole quality. The paper shows the efficiency of the developed research solution can reach 5 s per hole including drilling and full cycle of measurements having measurement error of 1–3%.
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| 7. |
- Johansson, Daniel, et al.
(författare)
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Tool Life and Wear Model in Metal Cutting, Part 1 - Influence of Varying Flank Wear Criterion on Colding's Tool Life Equation
- 2014
-
Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- The tool life model formulated by Bertil Colding is limited to the use of a specified tool life criterion. The Colding equation describes the relationship between tool life, cutting speed and the equivalent chip thickness. The Colding equation is based on five constants which have unique values for each selected value of the tool life criterion. This paper investigates how these Colding constants can vary for different selected wear criteria.
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| 8. |
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| 9. |
- Johansson, Jakob, et al.
(författare)
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Hot Forging Operations of Brass Chips for Material Reclamation after Machining Operations
- 2017
-
Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 11, s. 584-592
-
Tidskriftsartikel (refereegranskat)abstract
- The production of chips is an inevitable part of any machining operation. Today, brass chips are commonly recycled through re-melting by the material supplier implying a “loop” where material is sent back and forth between the material supplier and the manufacturing company. The research presented in this paper evaluates a method for compaction and hot forging of brass chips into blanks for subsequent machining into a finished product. A series of experiments have been performed to evaluate the method. The results indicate a possibility of a successful hot forging method for brass chips into machining blanks.
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| 10. |
- Laakso, Sampsa, et al.
(författare)
-
Multi-objective testing of different brass alloy components for DFM
- 2019
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Ingår i: 52nd CIRP Conference on Manufacturing Systems (CMS), Ljubljana, Slovenia, June 12-14, 2019. - : Elsevier BV. - 2212-8271. ; 81, s. 127-132
-
Konferensbidrag (refereegranskat)abstract
- This paper investigates the differences of leaded and low-lead brasses in terms of mechanical and thermal properties, machinability and product strength using physical testing and simulations. The information can be used in companies for Design for Manufacturability (DFM) while designing processes for lead free brass. The novelty of this research is to combine data from different testing methods to a unified model that can be used in both cutting simulations and product simulations.
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| 11. |
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| 12. |
- Lindström, Alexander, et al.
(författare)
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Cost Analysis for Crushing and Screening: Development of a Methodology for Determination of Production Cost for Product Fractions
- 2014
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Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- The comminution processes are complex and there has thus far been no, previously published, efficient way to calculate the cost per product and metric ton. The proposed model has been adapted to fit the currently investigated process of crushing and screening (C&S). Deriving from the original model, the proposed new model is presenting the result in cost per metric ton of raw material. It has been indicated to be a useful approach for calculation of the production cost and deciding the profitability of a product on a more detailed scale, in the comminution industry.
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| 13. |
- Olsson, Mike, et al.
(författare)
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Machinability of Ductile Single-Phase Materials Used in Accelerator Components - A Study with Focus on Surface Integrity
- 2014
-
Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- The focus of this article has been to analyse the machinability, with focus on surface integrity, of oxygen-free copper (OFC) and niobium during turning operations. The results from machining OFC proved that all of the tools that was tested can be used to achieve a surface roughness below Ra = 0.8 µm with the correct cutting data. From the results when machining niobium it showed that only the cemented carbide tool with a nose radius of 1.2 mm was able to achieve a surface roughness of Ra = 0.8 µm or greater. The cutting resistance based on the measured cutting forces was high for both of the materials.
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| 14. |
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| 15. |
- Reddy, Vijeth Venkataram, 1990-, et al.
(författare)
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Lead free Brass : Topography Characterization
- 2016
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Konferensbidrag (refereegranskat)abstract
- The negative effects of lead on human health and the recycling problems of copper alloys with lead content has led to the increase in concern for reducing/eliminating the use of lead in brass and other copper alloys. Many materials are considered to replace lead in brass; silicon is one such alternative. The real challenge prevails in sustainable manufacturing of lead free brass, to maintain control of the surface integrity when substituting the lead content in the brass with silicon. The investigation includes defined areal surface parameters measured on the turned samples of lead- and lead free brass using an optical coherence scanning interferometer, CSI.This paper deals with the study of surface topography of turned samples of lead and lead free brass. It is important to study the topographical characteristics of the brass samples which are the intermediate link between the manufacturing process variables and the functional behaviour of the surface. To numerically evaluate the sample’s surface topography and to validate the measurements for a significant study, a general statistical methodology is implemented. The results suggest that the surface roughness is higher in lead brass compared to lead free brass and tool coatings have significant influence on the hybrid (Sdr & Sdq) parameters in the surface topography of brass samples.
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| 16. |
- Reddy, Vijeth Venkataram, 1990-, et al.
(författare)
-
Surface topography characterization of brass alloys : lead brass (CuZn39Pb3) and lead free brass (CuZn21Si3P)
- 2017
-
Ingår i: Surface Topography: Metrology and Properties. - Bristol : Institute of Physics Publishing (IOPP). - 2051-672X. ; 5:2
-
Tidskriftsartikel (refereegranskat)abstract
- Manufactured surfaces usually consist of topographical features which include both those put forth by the manufacturing process, and micro-features caused by disturbances during this process. Surface characterization basically involves study of these features which influence the functionality of the surface. This article focuses on characterization of the surface topography of machined lead brass and lead free brass. The adverse effect of lead on human health and the environment has led the manufacturing sector to focus on sustainable manufacturing of lead free brass, as well as how to maintain control of the surface integrity when substituting the lead content in the brass with silicon. The investigation includes defined areal surface parameters measured on the turned samples of lead- and lead free brass using an optical coherence scanning interferometer, CSI. This paper deals with the study of surface topography of turned samples of lead-and lead free brass. It is important to study the topographical characteristics of the brass samples which are the intermediate link between the manufacturing process variables and the functional behaviour of the surface. To numerically evaluate the sample's surface topography and to validate the measurements for a significant study, a general statistical methodology is implemented. The results indicate higher surface roughness in turned samples of lead brass compared to lead free brass. © 2017 IOP Publishing Ltd
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| 17. |
- Schultheiss, Fredrik, et al.
(författare)
-
A step towards sustainable machining through increasing the cutting tool utilization
- 2013
-
Ingår i: Green Design, Materials and Manudacturing Processes. - 9781138000469 ; , s. 191-196
-
Konferensbidrag (refereegranskat)abstract
- Machining is an important and widely spread manufacturing method which should not be neglected while striving towards sustainable production. Several previous articles have discussed sustainable machining and different approaches towards reaching this goal. However, few have discussed the influence of the cutting tool utilization on the sustainability during machining. This article presents a novel approach of increasing the tool utilization during both turning and milling operations. Experimental results show that by utilizing the cutting tools more efficiently it is possible to increase the tool life by up to 100 % depending on machining scenario. Thus, a significant step towards sustainable production could be made.
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| 18. |
- Schultheiss, Fredrik, et al.
(författare)
-
A Sustainable Approach for Milling of Duplex Stainless Steel by Increasing the Cutting Tool Utilization
- 2012
-
Ingår i: Proceedings of the 5th International Swedish Production Symposium. - 9789175197524 ; , s. 171-177
-
Konferensbidrag (refereegranskat)abstract
- Common practice in industry is to rotate the milling cutter in only one direction even though the geometry of the inserts are thus that they could be used again while the milling cutter is rotating in the opposite direction. The aim of this study was to investigate to what extent it is possible to increase the tool utilization during milling by first rotating the milling cutter in one direction until the inserts were considered as worn out according to the conventional standard. Afterwards the inserts where used in another milling head which rotated in the opposite direction. The experiments were conducted while milling duplex stainless steel SAF 2304. This due to that machining of duplex stainless steel is often thought of as leading to adhesive wear of the cutting tool which added an important type of tool wear to the investigation in addition to the dominating abrasive wear. The experimental results show that by rotating the milling cutter in both directions it was possible to increase the tool utilization with approximately 80 %.
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| 19. |
- Schultheiss, Fredrik, et al.
(författare)
-
Analysis of the minimum chip thickness during turning of duplex stainless steel
- 2018
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture. - : SAGE Publications. - 0954-4054 .- 2041-2975. ; 233:7, s. 1733-1744
-
Tidskriftsartikel (refereegranskat)abstract
- The goal of this study has been to establish a method for quantifying the minimum chip thickness, h1min, during longitudinal turning of duplex stainless steel, and explore how the value of h1min changes with varying process parameters. Based on experimental results, it was found that the tool edge radius only has a limited influence on the size of h1min up to a certain feed level after which the chip flow direction close to the nose radius will have an increasingly pronounced effect. Experimental results show that h1min may be as large as 40% of the theoretical chip thickness when machining duplex stainless steel, results which were corroborated by an finite element method (FEM) analysis. Thus, it can be concluded that a substantial amount of workpiece material will only be deformed onto the machined surface or will form the side flow and not removed as a chip.
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| 20. |
- Schultheiss, Fredrik, et al.
(författare)
-
Comparative Study on the Machinability and Manufacturing Cost in Low-Lead Brass
- 2016
-
Ingår i: Proceedings of the 26th International Conference on Flexible Automation and Intelligent Manufacturing. ; , s. 496-503
-
Konferensbidrag (refereegranskat)abstract
- Today, commercially used brasses commonly contain 2 to 4 wt.% lead. As the availability of low-lead and lead-freebrass increase, there are environmental incentives for investigating the consequences of replacing thelead-containing brasses with lead-free equivalents. Generally, lead-free brass is expected to have a lowermachinability than its lead-alloyed counterpart, implying a higher manufacturing cost. Thus, the aim of this studyhas been to quantify the added manufacturing cost by replacing a standard brass alloy with a low-lead alternative.This was done through a case study performed at a Swedish SME which replaced CuZn39Pb3 (3.3 wt.% Pb) withlow-lead CuZn21Si3P (<0.09 wt.% lead) for a select part. Since CuZn21Si3P is almost twice as expensive asCuZn39Pb3, the material cost was found to have a substantial influence on the manufacturing cost. Additionally,the lower machinability implied a longer cycle time and higher losses while machining CuZn21Si3P, resulting in a77% overall increase in manufacturing cost when using the low-lead material. Arguably, the difference in materialcost, and thus manufacturing cost, may decrease over time making production of low-lead and lead-free brassproducts a viable option, especially when considering the environmental incentive for decreasing the amount oflead in circulation.
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| 21. |
- Schultheiss, Fredrik, et al.
(författare)
-
Comparative study on the machinability of lead-free brass
- 2017
-
Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 149, s. 366-377
-
Tidskriftsartikel (refereegranskat)abstract
- Lead is a heavy metal which is toxic even at low exposure levels. Although the amount of lead used in industry is steadily declining, it still constitutes a common alloying element for most conventional brass varieties. Today, conventional brasses contain roughly 3 wt % lead. One of the main incentives for using lead as an alloying element is that it has a markedly positive effect on the machinability of the workpiece material. However, as an increasing amount of lead-free brasses are becoming commercially available and future legislative actions could be expected, even further limiting the use of lead as an alloying element, there is a renewed interest in evaluating the machinability of these new lead-free materials. The current article focuses on evaluating the machinability of the commonly used, lead-containing, CuZn39Pb3 brass as compared to the commercially available, lead-free alternative CuZn21Si3P. An improved understanding of the difference in machinability was obtained by comparing the properties and behavior of these two materials in machining. For instance, it was noted that the tool wear is significantly higher while machining CuZn21Si3P as compared to CuZn39Pb3 under similar conditions. This can, to a certain extent, be counteracted through the use of inexpensive tool coatings, making lead-free brass a viable option for commercial production.
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| 22. |
- Schultheiss, Fredrik, et al.
(författare)
-
Cost Based Process Optimization by Incrementally Changing the Cutting Data during Sustainable Machining
- 2012
-
Ingår i: Advanced Materials Research. - 1022-6680. ; 576, s. 742-746
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Tidskriftsartikel (refereegranskat)abstract
- All companies strive towards lowering their manufacturing costs. Few companies do however succeed in continuously improving their production after the launch of a new production process. This article introduces a method for companies having an established technology to optimize their production in terms of part cost without disrupting the normal, day-to-day production. By incrementally chancing the process parameters such as for example cutting data as a function of the originally selected values, it is possible to optimize the production process. This is closely related to the lean production philosophy and long term sustainability which strives towards efficient use of resources and involvement of all employees in improving the production process. In the case study presented in this article it was found that by adding extra sulfur to the cutting fluid it was possible to decrease the part cost. By using the proposed method the company was able to decrease the part cost when manufacturing a specific part with approximately 5 %.
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| 23. |
- Schultheiss, Fredrik, et al.
(författare)
-
Cost Optimization by Incremental Production Improvements of Metal Cutting Operations
- 2011
-
Ingår i: [Host publication title missing]. ; , s. 540-547
-
Konferensbidrag (refereegranskat)abstract
- The focus of this project has been to find a method on how to do production improvements systematically in the case of manufacturing by means of metal cutting operations. Typically every company determines their cutting data with the help of previous experiences as well as recommendations made by the tool manufacturers. These chosen cutting data may be the optimal settings for the specific operation although the probability for this is very slim. Some large companies have resources to investigate and find the optimum cutting data by themselves but this is usually not the case for SMEs. These companies need a clear and logical method on how to find the machining optimum while not causing too many delays or scraped parts during the normal production. The goal of this research was to find a method to incrementally optimize the production in terms of manufacturing costs of the machined parts in SMEs. The proposed method is illustrated by an analysis of the results obtained from a case study at a small Swedish company. The present work constitutes a good foundation for the optimization of the production process and thereby has a strong relevance toward the area of sustainable production.
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| 24. |
- Schultheiss, Fredrik, et al.
(författare)
-
Experimental Study of the Minimum Chip Thickness during the Machining of Duplex Stainless Steel
- 2011
-
Ingår i: AMST'11 - Advanced Manufacturing Systems and Technology. - 9789536326648 ; , s. 175-189
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Konferensbidrag (refereegranskat)abstract
- During a machining operation the workpiece material at some point has to split up into two separate material flows forming the chip and machined surface respectively. In the boundary zone between these two different flows of material it is possible to distinguish a stagnation point. This stagnation point is closely related to the minimum chip thickness h1min. The size of h1min is of great interest due to how it describes the material flow into the machined surface and thus giving information on the workpiece surface deformation. The goal of this study has been to find a method to experimentally measure the size of h1min and to investigate how this variable changes with different process parameters such as cutting data and tool edge geometries. The obtained results show that h1min in several cases may be as large as 40% of the theoretical chip thickness h1 when machining duplex stainless steel.
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| 25. |
- Schultheiss, Fredrik, et al.
(författare)
-
Influence of the minimum chip thickness on the obtained surface roughness during turning operations
- 2014
-
Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 13, s. 67-71
-
Konferensbidrag (refereegranskat)abstract
- Considerable efforts have been put into analyzing the obtained surface roughness during turning operations. However, knowledge is still lacking on how to model the arithmetic mean surface roughness Ra through using a general model applicable for all workpiece materials and process parameters. Further, the influence of the minimum chip thickness on the obtained surface roughness needs to be clarified. This article presents a new model for predicting the Ra surface roughness during turning operations. The model is based on physical and empirical knowledge of the turning process and has been experimentally validated through turning Al-SiCp MMC, cast iron, conventional- and stainless steels, as well as Ti6Al4V. The obtained results show great potentials with an average error of 6.7% even though errors as large as 16.6% were obtained for some cases.
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| 26. |
- Schultheiss, Fredrik, et al.
(författare)
-
Influence of the tool surface micro topography on the tribological characteristics in metal cutting - Part II Theoretical calculations of contact conditions
- 2013
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 298, s. 23-31
-
Tidskriftsartikel (refereegranskat)abstract
- The tribological conditions at the contact between the cutting tool and the chip are of great importance when analyzing the machining process. By knowing the contact conditions on the rake face of the cutting tool the wear on the clearance and rake face may be predicted in terms of size and type of wear. A certain value of the surface stresses is often thought of as leading to a higher wear rate of the cutting tool and thus a shorter tool life. In this article two different methods for experimentally measuring the contact condition on the clearance and rake face of the cutting tool are presented and illustrated with results obtained while turning AISI 4140. Results are also obtained in terms of how the surface roughness value of the cutting tool influences the contact condition. It was found that the tool surface topography may have a significant impact on the tribological performance during machining.
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| 27. |
- Schultheiss, Fredrik, et al.
(författare)
-
Influence of the Workpiece Material Properties on the Cutting Forces
- 2014
-
Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- This study focuses on modelling the cutting resistance as a function of the workpiece material properties. Thus, for a workpiece material the cutting resistance may be predicted from the material properties without using any experiments. The cutting resistance may then be used to determine the cutting forces, data which in turn may be used to determine appropriate process parameters and select cutting tools for a new machining operation. The model obtained produces adequate results having a variation coefficient of approximately 5 to 16 % as compared to measured values.
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| 28. |
- Schultheiss, Fredrik, et al.
(författare)
-
Machinability and manufacturing cost in low-lead brass
- 2018
-
Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 99:9-12, s. 2101-2110
-
Tidskriftsartikel (refereegranskat)abstract
- Today, commercially used brasses commonly contain 2 to 4 wt% lead. As the availability of low-lead and lead-free brass increases, there are environmental incentives for investigating the consequences of replacing the lead-containing brasses with lead-free equivalents. Generally, lead-free brass is expected to have a lower machinability than its lead-alloyed counterpart, implying a higher manufacturing cost. Thus, the aim of this study has been to quantify the added manufacturing cost by replacing a standard brass alloy with a low-lead alternative. This was done through a case study performed at a Swedish SME which replaced CuZn39Pb3 (3.3 wt% Pb) with low-lead CuZn21Si3P (< 0.09 wt% lead) for a select part. Since CuZn21Si3P is almost twice as expensive as CuZn39Pb3, the material cost was found to have a substantial influence on the manufacturing cost. Additionally, the lower machinability implied a longer cycle time and higher losses while machining CuZn21Si3P, resulting in a 77% overall increase in manufacturing cost when using the low-lead material. Arguably, the difference in material cost, and thus manufacturing cost, may decrease over time making production of low-lead and lead-free brass products a viable option, especially when considering the environmental incentive for decreasing the amount of lead in circulation.
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| 29. |
- Schultheiss, Fredrik, et al.
(författare)
-
Machinability of CuZn21Si3P brass
- 2016
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 1743-2847 .- 0267-0836. ; 32:17, s. 1744-1750
-
Tidskriftsartikel (refereegranskat)abstract
- New brass alloys containing less or even no lead are being developed, decreasing the environmental impact of the material. One example of an alternative brass is CuZn21Si3P, which contains less than 0.09 wt-% Pb. The research presented in this article evaluates the machinability of CuZn21Si3P as compared to more common, lead-containing free-machining brasses. The results show a marked decrease in the machinability of CuZn21Si3P. When longitudinally turning CuZn21Si3P the cutting tool failed after 142 min of machining. This tool wear was to a large extent remedied through the use of a coating on the cutting tool. CuZn21Si3P appears as a viable substitute for lead-containing brasses, thus implying the possibility for improving the sustainability of modern production.
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| 30. |
- Schultheiss, Fredrik, et al.
(författare)
-
Machinability of duplex stainless steels - A study with focus on the tool wear behaviour
- 2011
-
Ingår i: [Host publication title missing]. ; , s. 271-277
-
Konferensbidrag (refereegranskat)abstract
- This article presents research done in order to analyse the machinability of duplex stainless steel with coated carbide tools during turning operations. Although duplex stainless steel has existed for about 70 years fairly little work has been published in the area of investigating the different aspects of the machining of these materials. In this research project three different kinds of duplex stainless steels and their properties have been examined. These materials where SAF 2507, SAF 2205 and LDX 2101 which together covers a large part of the duplex stainless steels that are commercially available today. This study focuses on analysing the tool wear behaviour in an attempt to better understand the actual wear patterns during machining, not only the more traditional ones that are in common use today. Some additional tests were also done in order to get a better understanding of the machinability of duplex stainless steel in general. Theories and concepts that are related to the analysing of machinability will be presented, most of which have been previously validated and in use for a long time. Adhesive wear of the cutting tool, in many cases severe, was to some extent found at all different cutting data investigated.
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| 31. |
- Schultheiss, Fredrik, et al.
(författare)
-
Machinability of Lead-Free Brass – A comparative study
- 2014
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Ingår i: Proceedings of the 6th Swedish Production Symposium.
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Konferensbidrag (refereegranskat)abstract
- Convetional brass is still allowed to contain up to 3.5 wt.% lead even though lead is a hazardous metal. However, due to environmental concerns lead-free brasses are becoming increasingly available. The aim of this paper is to evaluate the machinability of a lead-free brass alloy, CuZn21Si3P, as compared to a convetionally used, lead-alloyed alternative, CuZn39Pb3. The attained results show that CuZn21Si3P has a considerably higher strength than the lead-alloyed material resulting in significantly higher cutting forces. This increase in cutting forces was found to result in more rapid deterioration of the cutting tool, raising concerns for higher manufacturing cost if not properly adressed.
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| 32. |
- Schultheiss, Fredrik, et al.
(författare)
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Modeling the cost of varying surface finish demands during longitudinal turning operations
- 2016
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Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 84:5, s. 1103-1114
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Tidskriftsartikel (refereegranskat)abstract
- Tolerances, including geometry, dimension, and surface roughness, are an important part of production where the desire to manufacture quality products have to be weighed against the increase of manufacturing costs. The desired tolerance will influence the choice of both manufacturing method and machine tool. Given that machining is an adequate production method, variation of the required tolerances will imply a variation of the part cost which needs to be taken into account during production planning. Thus, the term “tolerance cost” is introduced. The paper presents a model for evaluating the tolerance cost in respect to the surface roughness during longitudinal turning operations, enabling a better comparison between different production alternatives. Through knowledge of the required surface roughness, it is possible to estimate appropriate cutting conditions. Knowledge of the cutting conditions and the part geometry then makes it possible to calculate the cycle time, information which in turn may be used for calculating the corresponding part cost. Through using experimental data, it is proven that the required surface roughness has a significant influence on the attained manufacturing cost. For instance, while longitudinally turning AISI 4140, it was shown that an improvement of the surface roughness from Ra=3.2 μm to Ra=1.6 μm will entail an increase of the part cost by roughly 20 %. Similarly, a decrease of the required surface quality (larger Ra value) will imply a significantly reduced part cost.
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| 33. |
- Schultheiss, Fredrik
(författare)
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On the Machinability of Ductile and Strain Hardening Materials - Models and Methods for Analyzing Machinability
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As quality and performance demands on today’s products increases, more and more advanced materials are being used during modern production. The problem is however that this in turn place new demands on the machining processes utilized. Even though a significant amount of research has been published on the machining of these materials knowledge is still limited in several crucial areas. A problem with machining research is that it often relies heavily on quantitative data primarily obtained through experimental investigations. Due to the substantial amount of potentially different machining cases it could be difficult to generalize the obtained results to other scenarios. In this dissertation it has been attempted to model the investigated phenomena through using universal physical relationships. Even though this might result in a larger modeling error for the specific case investigated the author sees a great advantage of being able to have a physical explanation to the obtained results. The aim of this dissertation has been to increase the knowledge on, and to a certain extent predict, the machinability of some common ductile and strain hardening materials. The research has focused on evaluating duplex stainless steel, Ti6Al4V and Alloy 718. However, the proposed models have been constructed in a way as to aid future implementation for other workpiece materials. A central pillar of the research has been the influence of the stagnation point and the related minimum chip thickness. This aspect influences all machining operations and could potentially have a significant impact on the machinability, not least for ductile and strain hardening materials. During this research it was found that even though cutting conditions have a major influence on the value of the minimum chip thickness, material factors such as ductility and strain hardening should not be neglected as these also influence the obtained value. In turn, it was found that the minimum chip thickness could to a certain extent be used to explain the obtained workpiece surface roughness. Also, the tool surface roughness was found to have a determinate influence on the mechanics of the machining process. During the present research it was also found that it is difficult to predict the tool life using conventional models for the investigated materials, essentially due to their high strength at elevated temperatures, adhesive behavior during machining, and low thermal conductivity. The influence of these properties commonly results in rapid and unpredictable wear of the cutting tool. Plastic deformation of the cutting tool is always a concern when machining these materials and a first step towards establishing a method for measuring the initiation of plastic deformation by using the measured cutting force has been proposed. Also, through using a proposed method for determining the potential machinability of a specific workpiece material these effects could be reduced through the use of reasonable process parameters before commencing production. Methods for improving the machining process in terms of for example part cost or sustainability has been developed as part of this research. Even though each of these methods only improves a small part of the whole production process these improvements should not be neglected as all parts of the process should be optimized in order to achieve a truly sustainable and cost efficient machining process.
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| 34. |
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| 35. |
- Schultheiss, Fredrik, et al.
(författare)
-
Sustainable machining through increasing the cutting tool utilization
- 2013
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 59, s. 298-307
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Tidskriftsartikel (refereegranskat)abstract
- Several previous articles have discussed different approaches to improving sustainability during machining operations. However, more effective utilization of cutting tools is an approach that has been overlooked in previous investigations. Increasing the effectiveness of cutting tool utilization decreases the need for new tools as well as the resources and energy needed to produce new cutting tools. The aim of this study was to maximize cutting tool utilization during machining operations without adversely affecting product quality, thus decreasing the environmental impact of machining operations. This was achieved by determining to what extent it is possible to increase total tool life by using previously worn tools in a secondary machining operation. For both the milling and turning cases investigated, experimental results showed that it is possible to increase the total tool life by approximately 50% to 100% compared to equivalent conventional machining operations. The increase in tool life could decrease the production cycle time by approximately 15% and reduce energy consumption by 12% as compared to conventional machining processes.
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| 36. |
- Schultheiss, Fredrik, et al.
(författare)
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Tool Wear Mechanisms of pcBN tooling during High-Speed Machining of Gray Cast Iron
- 2018
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Ingår i: 8th CIRP Conference on High Performance Cutting (HPC 2018). - : Elsevier BV. - 2212-8271. ; 77, s. 606-609
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Konferensbidrag (refereegranskat)abstract
- The presence of graphite particles in gray cast iron commonly implies a good machinability, especially if compared to common steels. However, increasing industrial demands have resulted in a new interest for high-speed machining of these materials with higher performing tool materials than the traditionally used. Thus, the research presented in this paper focuses on evaluating the active tool wear mechanisms while high-speed machining EN-GJL-250 gray cast iron with pcBN tools with different composition, geometries and edge preparations. In addition to the expected flank and notch wear, formation of MnS, SiO2, and Al2O3 tool protection layers was found on the worn surfaces. Non-chamfered tools exhibited higher tendency towards notching. In general, the tools were found to have a rather small wear land but large edged radius indicating edge rounding being a more accurate wear criterion.
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| 37. |
- Stahl, J. E., et al.
(författare)
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Analytical and experimental determination of the Ra surface roughness during turning
- 2011
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Ingår i: Procedia Engineering (1st CIRP Conference on Surface Integrity, CSI 2012; Bremen; 30 January 2012 through 1 February 2012; Code 87787). - : Elsevier BV. - 1877-7058. ; 19, s. 349-356
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Konferensbidrag (refereegranskat)abstract
- In this article an analytical equation for calculating the theoretical arithmetic mean surface roughness, Ra, in the case of turning using a tool with a circular nose radius is presented. The deviation that often occurs between the expected and the obtained surface roughness during these machining operations is investigated. Influence of the minimum chip thickness is discussed especially in regards to the related phenomenon of so called side flow of material on the machined surface. Three different kinds of workpiece materials have been investigated in order to gain a better understanding of their influence on the obtained surface roughness. The obtained results show that the surface roughness could be considered as being inside an interval of two analytically determined Ra-values. © 2012 Published by Elsevier Ltd. Selection and peer-review under responsibility of Prof. E. Brinksmeier.
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| 38. |
- Ståhl, Jan-Eric, et al.
(författare)
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Analytical Calculation of the Ra Surface Roughness during Turning
- 2012
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Ingår i: Proceedings of the 5th International Swedish Production Symposium. - 9789175197524 ; , s. 185-190
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Konferensbidrag (refereegranskat)abstract
- In this article an analytical equation for calculating the theoretical arithmetic mean surface roughness, Ra, in the case of turning using a tool with a circular nose radius is presented. The calculated Ra-values are verified by experimental results obtained from machining of 7 different workpiece materials. For all measuring series results were obtained that were either better or worse than the theoretically calculated values. The presented model describes an analytical equation for calculating the theoretical Ra-value and may be practically implemented in industry.
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| 39. |
- Ståhl, Jan-Eric, et al.
(författare)
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Analytical Calculation of the True Equivalent Chip Thickness for Cutting Tools and its Influence on the Calculated Tool Life
- 2012
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Ingår i: Advanced Materials Research. - 1022-6680. ; 576, s. 80-86
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Tidskriftsartikel (refereegranskat)abstract
- A majority of the established systems for determination and optimization of cutting data are based on Woxén’s equivalent chip thickness, heW. In metal cutting theory and models, the equivalent chip thickness is of vital importance when the depth-of-cut ap is in the same order or smaller than the nose radius r. Woxén made considerable simplifications in his chip area model, that form the basis for calculations of the equivalent chip thickness. Basic mathematical solutions, e.g. describing the chip area on circular inserts, are lacking. This article describes the geometrical implications when machining with round inserts. The error in Woxén’s equivalent chip thickness is largest when the depth-of-cut is less than ¼ of the nose radius and are up to 40 % wrong for some combinations of cutting data in the finishing range. The presented results explain the difficulties in getting a good validity in the models used to calculate tool life in finishing machining. The error leads to an underrating of the tool load in many machining situations.
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| 40. |
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| 41. |
- Ståhl, Jan-Eric, et al.
(författare)
-
Metallmatriskompositer i masstillverkade komponenter och produkter : - MMC 2016-2018
- 2018. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Föreliggande rapport beskriver forskningsarbetet inom projektet: ”Utveckling av MMC för högpresterande aluminiumkomponenter – Vinnova 2015–05072 som leds av Marie Fredriksson vid Swerea SWECAST i Jönköping. Redovisade resultat bygger också på tidigare kunskaper och tidigare projekt som forskargruppen vid Lunds universitet genomfört. Resultaten från detta arbete visar att det kan vara fullt möjligt att masstillverka komponenter i MMC under rätt förutsättningar. Det finns goda möjligheter för att lyckas realisera MMC i bruksprodukter även om ytterligare forskning och utveckling krävs. En sekventiell tillverkning bestående av gjutning av enkelt ämne, smidning till nära slutlig form och en viss omfattning av skärande bearbetning kan ge en konkurrensmässig tillverkning i förhållande till etablerade koncept. Industriellt kommer det att krävas investeringar i ny utrustning samtidigt som nya produkter måste konstrueras och anpassas till MMC och dess tillhörande tillverkningsteknologier.
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| 42. |
- Ståhl, Jan-Eric, et al.
(författare)
-
Tolerance Cost in Relation to Surface Finish during Longitudinal Turning Operations
- 2014
-
Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- Tolerances are an important part of production where the desire to produce quality products have to be weighed against the increased production costs. The desired tolerance will influence the choice of both production method as well as the machine used. Given that machining is an adequate production method, variation of the required surface roughness will imply a variation of the part cost which needs to be taken into account during production planning. This paper presents a method for evaluating the tolerance cost in regards to surface roughness during longitudinal turning operations, thus enabling a better comparison between different production situations.
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| 43. |
- Ståhl, Jan-Eric, et al.
(författare)
-
Tool Life and Wear Modelling in Metal Cutting, Part 2 ─ Based on Combining the Archard and the Colding Equations
- 2014
-
Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- In this article an analytical and empirical model for describing tool life and tool wear in metal cutting is presented. The model is based on combining the Colding tool life equation and an extended version of the Archard wear function. It is shown that through the combining of these two models a substantial saving of resources can be achieved in terms of the workpiece material required, as well as the manpower and machine time needed for determining the model constants and the optimum cutting data to be employed.
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| 44. |
- Tam, Eric, 1980, et al.
(författare)
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Residual stress analysis of machined lead-free and lead-containing brasses
- 2016
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 1743-2847 .- 0267-0836. ; 32:17, s. 1789-1793
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Tidskriftsartikel (refereegranskat)abstract
- Legislations demand low lead content in drinking water and low lead leaching from the water supply facilities. Lead-free brass (LFB) can fit in. The benefits of such alloy are acknowledged in both functional and environmental points of view. The relatively high strength of LFB means that the process condition and residual stress generation can be different as compared to the conventional brass. In this study, residual stress generation for a LFB (CuZn21Si3P) and a lead-containing brass (CuZn39Pb3) in a face-turning experiment is studied. Besides stress analysis, structural characterisation is also conducted. Stress generation in the feed and cutting directions of two brasses is depicted. Machined topography is measured to evaluate the surface integrity in connection with the machining conditions.
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| 45. |
- Vosough, Manouchehr, et al.
(författare)
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A method for identification of geometrical tool changes during machining of titanium alloy Ti6Al4V
- 2013
-
Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 67:1-4, s. 339-348
-
Tidskriftsartikel (refereegranskat)abstract
- There exists an increasing demand for cost and time efficient cutting tests for describing the performance of different combinations of cutting tools and workpiece materials in the cutting process both in industry and academia. Cutting tools are expected to withstand the heat and the pressure developed during the machining of difficult to machine materials such as Ti6Al4V. This article introduces a new test method which may be used in order to analyze both the machinability of a workpiece material as well as the cutting tool behavior. The experiments were performed by using a predefined sequence of feeds, a so called Stepwise Increased Feed Test (SIFT). A gradually increased load on the cutting edge was thus applied up to the point where plastic deformation of the cutting edge was obtained. The limit for the initial change in tool geometry was identified through analysis of measured cutting forces.
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| 46. |
- Windmark, Christina, et al.
(författare)
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Batch size optimization based on production part cost
- 2014
-
Ingår i: FAIM 2014 - Proceedings of the 24th International Conference on Flexible Automation and Intelligent Manufacturing: Capturing Competitive Advantage via Advanced Manufacturing and Enterprise Transformation. - 9781605951737 ; , s. 1031-1038
-
Konferensbidrag (refereegranskat)abstract
- When investigating different location and/or system designs the possible variables to take into consideration can differs between the alternatives. Different production system will have different optimal working conditions and hence should be compared with parameters suitable for the actual production system. When planning production and calculating production costs the batch size is of high interest. Based on a manufacturing part cost model, this paper will present a new model, close connected to the production system, integrating production performance, set-up times, material costs, material handling costs and tied capital, giving the production economic optimal batch size. The aim is to give companies a model for determining the economic optimal batch size in order to use this knowledge to make strategic decisions regarding production planning. Mathematical simulations are performed to analyse the differences in result from the developed model and Wilsons existing standard method for calculating the economic order quantity, hence to verify the importance of making an in-depth analysis, taking the production system into consideration. The advantage of the developed model is the usage of production costs based on variable batch sizes, giving a more accurate outcome.
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| 47. |
- Xu, Linhong, et al.
(författare)
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General Conception of Polar Diagrams for the Evaluation of the Potential Machinability of Workpiece Materials
- 2013
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Ingår i: International Journal of Machining and Machinability of Materials. - 1748-572X. ; 14:1, s. 24-44
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a polar diagram method developed for describing and evaluating the potential machinability of different workpiece materials. The potential machinability is examined in terms of five critical properties of the workpiece material. Two groups of materials, a group of common steel grades and the other a group of stainless steels, were examined in detail, their polar diagrams illustrating the potential for comparing the machinability of different workpiece materials. Polar diagrams are seen as being particularly helpful in setup work for the machining of new, previously unknown materials as it allows for comparison with other materials and their respective machinability.
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