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Tape Finishing

Fields of applications
Machining of radii with

Type series of the machines
Working example crankshaft

Deep Hole Drilling Machines
Assembly & Leak Testing Machines
Leak Testing Machines


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Tape Finishing

PERMAT supplies tape finishing machines for crankshafts and camshafts.

Click on the image opposite to see an enlarged view.

Fields of application
In engine manufacture for finish machining of:
Crankshafts for mains, crankpins, thrust faces, oil seal diameters.
In this case a surface suitable for its purpose is achieved, i.e. without cross-hatch pattern.
Camshafts at all bearing points
and additionally for the cam lobes.
Pump shafts with bearing seats
and oil seal diameters, nontwisting.
Lever arms and rocker arms with their spherical working and operationting faces for cam lobes
and valves, respectively.
Front faces of stroke curves on steering wheels.

In gear manufacture for manufacturing of:
Main shafts for sliding and roller raceways as well as bearing journals, i.e. needle bearing raceways.
Drive shafts and output drive
shafts with needle bearing raceways and oil seal diameters, nontwisting.


What is Tape Finishing?
Tape Finishing is a proven method of finish machining raceways for sliding and antifriction bearing. Polishing tape and microfinishing film serve as "cutting tool". The cutting tool is pressed against the component surface by means of formed tool shoes with half-elastic or hard supports which are hardly subject to any wear.

Technological features
Quick stock removal is achieved by two simultaneously working movements, i.e. by the component rotation in direction of rotation and the short-stroke oscillation movement in direction of the component axis. Thereby the surface quality is considerably improved. With each component change the finishing tape is feed forward to supply new unused cutting grains thus achieving constant conditions for stock removal and final quality in each working cycle.

One operation produces two results - cutting and smoothing. At first, the newly applied cutting medium with its very sharp grains produces a good cutting effect; stock is removed. In the further course of the finishing operation the cutting grains are flattened, break away, the finishing tape becomes loaded. Thus the smoothing effect is increased.

Tool monitoring = process security
With tape finishing the tape feed is monitored and tape end or tape breakage are checked in each working cycle. These tape detection facilities make it possible to link the machines in automatically working production plants without needing any additional monitoring staff.

In Motor and chassis
manufacture for bearing and oil seal raceways on:

Toothed racks of servo-steering.
Drive shafts.


Machining of radii with crankshafts

Here, not only the bearings but also the adjacent blended radii are intensively finish machined by tape finishing. This operation requires specially formed shoes in the basic tools, laterially slotted polishing tapes and a special control sequence.


Type series of the machines

Standard Tape Finishing Machine for manual loading and unloading directly into the working area. Moreover, for automatic linking, the design HF can be expanded by suitable gripping systems.


Transfer Tape Finishing Machine in one-or multi-station design, types TF/2 TF/3 TF, designed for linking with conveyor lines and for usage with magazine systems; also for rough and finish polishing and additional machining tasks.

UF            Back

Universal Tape Finishing Machine with flexible finishing units for components with different finishing positions, stroke sizes and bearing widths. Short change-over times are achieved by means of a quick-change facility for component-related change parts. Also available with NC-axes programs for automised adjustment functions.

Working example crankshaft

Description Machine Petrol engine (car) Diesel engine (truck)
Component length

Tensile strength
2 TF 6 4-cylinder crankshaft
455.0 mm
GGG 60
nodular graphite cast iron
HB 220-275
UF 10 6-cylinder crankshaft 785.0 mm alloyed steel hardened HRc 48-52
Machining task 5 x main bearing
4 x crankpins
2 x thrust face/axial bearing
2 x oil seal diameter
7 x main bearing 6 x crankpins 2 x thrust face/axial bearing 1 x oil seal diameter
Surface roughness
Ra 0.6-0.7
Rz 6-7
Ra 0.4-0.5
Rx 4-5
Cutting medium
Quality/grain size
Tape consumption
Stock removal on dia
micro finishing film
µl5 mill (Ron see symbols)
15 mmy/bearing point
0.004-0.006 mm
Polishing tape RB 346/320 2 x 20 mm/bearing point 0.006-0.010 mm
Surface roughness
After finishing
Machining time
Cycle time/machine
Machine output
Ra 0.2-0.25 µm
Rz 2-3
18 sec.
0.6 min
100 comp./h at 100% eff.
Ra 0.1-0.15 µm
Rz 1.0-1.25
2 x 20 sec.
1.6 min
36 comp./h at 100% eff.
Design principle of The finishing unit Master shaft principle Flexible design


Permat Machines Limited
Station Road, Coleshill, Birmingham
England B46 1JG
Tel: +44 01675 463351   Fax: 01675 465816
Telex: 336040

Nagel Maschinen-und
Werkzeugfabric GmbH
P.O. Box 1709 D-7440 Nurtingen
Tel: 07022 605-0   Telex: 7267337