VOL. 17 September ISSUE YEAR 2016


in Vol. 17 - September Issue - Year 2016
Stream Finishing Machine For Series Production
Automatic loading of the SF machine

Automatic loading of the SF machine

Suction nozzle for extracting the wastewater

Suction nozzle for extracting the wastewater

Before finishing

Before finishing

After finishing

After finishing

OTEC has developed the new SF 3/105 immersion-finishing unit with pulse-drive system specially to enable the system to be fully integrated into production lines for large-scale production runs. This unit type enables complex turned parts such as worm drives, gear wheels and camshafts to be deburred, rounded, burnished or polished in a matter of seconds. It is very easy to adjust the unit to the production cycle time, which is often only a few seconds.

How the machine works:

The workpieces are clamped by means of a mandrel or similar device. Loading can be carried out manually, by the use of a handling system or by a robot (especially for series production). Processing is carried out by immersing the workpiece in a flowing stream of grinding or polishing media. The media stream is generated by means of a rotating drum.

The pulse drive

The pulse drive system developed by OTEC delivers perfect results by rapidly alternating the direction of rotation. During this process, the clamped workpiece is immersed in a media stream of grinding or polishing media where it is alternately processed in each direction of rotation. Decelerating and accelerating again to 2,000 rpm takes only half a second. This creates relative velocities of up to 30 m/s and accelerations of up to 40 G. The main advantage of this is extremely short finishing times.

Additional features:
The angle of incidence can be adjusted by means of a servo motor and is therefore variable and can be changed automatically during the finishing process. Predefined positions can be processed and stored in the program so the flow can be adjusted according to the precise requirements of the workpiece.

A suction nozzle is fitted to continuously pump out the wastewater and the sludge from the wet finishing process. The benefits of this system are obvious:

Constantly high rates of material removal
No sludge in the process drum
Grinding and polishing media are always kept clean
Clean workpieces

Example: Finishing camshafts

Task: To deburr and round the edges to approx. 70 ?m whilst at the same time smoothing the surface from Ra 0.4 to under 0.2 ?m and an Rpk value of less than 0.1 ?m.


The finishing time required was approx. 30 seconds.
This means that with an SF 3 machine with three pulse drives, one workpiece would be finished every 15 seconds.



Ra values

0.4 ?m

0.09 ?m

Rpk values

0.4 ?m

0.06 ?m

Benefits for the customer
Less friction, reduced energy consumption
Our process reduces wear, since there is less friction
No run-in necessary - sharp points are rounded without chips being formed
Since no run-in is necessary, there is much less pollution of the oil, which increases oil change intervals by up to 100%
Up to 10% less heat generated
Up to 50 % less noise is generated than with conventionally ground parts

The right side pictures show an example of Rpk 0.2.
With the OTEC process, we can achieve Rpk values considerably under 0.1 ?m.

Camshaft measurements

The company:
OTEC is a medium-sized manufacturer of drag, disc and stream-finishing machines. Founded by Helmut Gegenheimer in 1996, the company has steadily established itself as a market leader by developing innovative new machine concepts and numerous patented processes.

For Information:
OTEC Präzisionsfinish GmbH
Heinrich-Hertz-Str. 24
75334 Straubenhardt-Conweiler
Tel. +49.7082.4911 20
Fax +49.7082.4911 29
E-mail: info@otec.de