Cold tube drawing provides higher accuracy compared to hot approaches. The process can be used to reduce the dimensions of tubes, and depending on the reduction size, the wall thickness of these may be subject to changes. In the process, any form of variability provoked by external factors is highly sensitive, given that the resulting tubes are often the final step in tube production. This paper focused on the evaluation of the influence of pre-tube factors on key variables after the drawing process, i.e., the final roundness, outer diameter, and wall thickness of the tubes. For these purposes, a factorial design with fixed factors was implemented. It was also a goal to investigate if the single-pass type of drawing would guarantee good statistical results potentially leading to significant time and financial reductions. The measurements were executed in the machine ZEISS CenterMax. The statistical analysis took place on Minitab 19. The results prove that most factors, and their interactions, significantly impacted the response variables, leading the authors to understand that a single-pass approach would not properly work under the conditions defined for the experimentation. These results also allow for reflection on the causes and necessary measures related to lubrication, technological heritage, and quality that would impact the results themselves.

This contribution proposes an optimization of material flow by means of modernizing of forging lines - type induction furnace / crank forging press / trimming press. The basis of design of forging line treatment is placement of hydraulic shear machine for shearing of heated bar to semi-products before respective forging of forged pieces. This method helped to remove previous redundant workplace for semi-products preparation, which causes reduction of technologic operations and substantial decrease of material flow in die forge. Proposed variant of material flow optimization brings economic profit by means of reduction of production times and fuels costs intended for pallets transport. Given save will be interesting for die forges as it contains also calculation of logistical effect.

Automotive industry is nowadays constantly strengthening its dominant position. Its primary objective is to reduce weight of automobiles in order to decrease fuel consumption and amount of harmful pollutant emissions. From the viewpoint of further development in the field of automotive industry, very interesting are the issues of die forgings production from light non-ferrous metals. This article describes research of precision die forging technology in closed die with regard to magnesium alloy type AZ 31. Given alloy type Mg-Al-Zn is suitable for bulk forming and is characterized by good formability at hot conditions. Results of this research may be applied to production of forgings with longitudinal shape, e.g. levers and connecting rods. In order to verify the design of forging technology in closed die for lever-shaped forged piece the simulation program MSC.SuperForge was used. Numeric simulation of die forging process confirmed suitable designed shape and dimensions of semi product and also correct material plastic flow in cavity of closed die.

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Abstract. Based on technological calculations, technology of one-operation drawing without blankholder was designed for production of a large-dimensional drawpiece with shape of welded on concave bottom. The necessary drawing force was also defined by calculation as maximum drawing force for trimming of drawpiece bottom. This contribution points out to the importance of FEM simulation of drawing process in order to verify the design of production technology of drawpiece with shape of welded on concave bottom on the basis of technological calculations. Simulation programme Deform verified the construction design of drawing tool determined for drawpiece production by first draw, and also determined the drawing force actually consumed during plastic deformation of drawpiece shape. Used simulation software confirmed correctness of drawing tool construction, as correct material plastic flow in drawing tool was monitored and production of drawpiece was faultless.