Ball-screw pairs of the S-HTF line from NSK allow the leading manufacturer of powder presses Osterwalder AG to use highly accurate and cost-efficient electric servo drives in their machines instead of traditional hydraulic ones.

The history of Osterwalder, headquartered in Lys (Switzerland), is more than 130 years old. Its powder presses are widely used in various industries, including the production of gears for automotive gearboxes and metalworking tools, such as drills and cutting plates. The metal alloy powder is poured into the mold and under pressure takes the desired shape. Then the intermediate product is sintered to obtain the desired characteristics of hardness, wear resistance and accuracy.

Osterwalder now offers a wide range of machine tools including the CA-SP Electric and CA-HM Electric direct-drive powder presses (DDT) launched 5 years ago, which include servo-electric motors and NSK ball screw pairs.

Thanks to DDT technology, powder presses can provide significantly higher accuracy than when using hydraulic drives. In addition, ball screws have increased rigidity compared with hydraulic cylinders. Thus, the products produced by servo-electric powder presses are more uniform, and the properties of their materials can be adjusted with increased accuracy. Due to this they managed to press the hydraulic drives prevailing in this area.

Initially, Osterwalder AG used NSK series HTF ball screws in servo-electric direct drives of CA-SP Electric and CA-HM Electric series presses. These ball screws allow you to set very high moving speeds in combination with increased accuracy and rigidity. At the same time, each node allows transmitting extremely high axial forces, and wear is minimal even under conditions of high loads and short cycles. The average cycle time of powder presses is 3 seconds.

Transition from HTF to S-HTF

DDT drives have proven themselves over the last 5 years: they were first used for pressing forces up to 160 kN, then - up to 640 kN. However, manufacturers required bearings and ball screws with a long service life.

NSK has developed a series of S-HTF ball-screw pairs with increased dynamic load-carrying capacity with the same dimensions and provide a much longer service life. Such technical characteristics were obtained through the use of the patented NSK TF (Tough Force) material, which is able not only to withstand high loads, but also to provide the optimum ratio of hardness and strength due to special heat treatment.

Tests have shown that TF technology leads to an increase in service life by 3 times, and dynamic load-carrying capacity - by 30% compared with the HTF series.

World premiere of the new powder press

Using the advantages of S-HTF ball screw pairs, Osterwalder developed and introduced OPP 2000, its first servo-electric multi-level powder press with a force of 2000 kN. It is able to provide positioning accuracy up to 1 micron and move according to specified movement profiles, which significantly improves product quality.

The new multi-level press is suitable for economical production of engine components, power tool parts, etc. The power consumption of such presses with servo is five times less than that of 20% of the power consumption of hydraulic presses. For users of presses, such savings are a weighty argument, since the typical customer Osterwalder simultaneously operates up to 50 powder presses.

NSK also supplies Osterwalder angular contact ball bearings in the TAC series for axial support of S-HTF ball-screw pairs. These bearings are designed specifically for use in high-precision machine tools. Usually they are installed in the form of complete system components for axial support and linear movement.

Podshipnik.ru, the leading supplier of industrial bearings in Russia, is the official distributor of NSK and offers the entire product range of this famous brand, including bearings and ball screw pairs.