The KELLER Film skiving machine - Precise skiving of extremely thin PTFE films for the high-tech industry
For more than 50 years, KELLER has been manufacturing film skiving machines which are reliably in use in Europe, North America and in the Far East and therefore has the longest and most extensive experience with film skiving machines worldwide. The high precision and accuracy of the film skiving machines is provided by a design that ensures an almost vibration-free skiving process of extremely thin films from 20 µm and a thickness tolerance of ± 3 µm.
Such high requirements are placed on films that are used, for example, as insulating material in electronic circuits or in solar collectors. Especially in the field of modern, digital communication technology for high-frequency lines and high-frequency antennas, the demand for high-precision films made of PTFE has increased significantly during the last years. In modern water treatment plants, the film serves as filter material.
With the proven machine type 8 PT 16 PTFE materials and other plastics with comparable properties - with a skiving billet diameter of up to 800 mm and a maximum skiving mandrel length of up to 1,600 mm - can be skived.
The mode of operation of the film skiving machine is similar to a conventional lathe
A plastic cylinder is clamped into the machine and is then rotated. A long knife approaches the cylinder from the side to skive the film.
If only everything were that easy
In order to be able to skive films of any thickness - setting range in steps of 1 µm - in the available working range - 20 µm to 5,000 µm - a combination of modern control and drive technology is used. Downstream equipment winds up the film or passes it on for further processing.
What makes the film skiving machine a high-precision machine?
The combination of a rigid frame construction and the high weight - approx. 12,000 kg - ensures an almost vibration-free machine.
Backlash-free bearing of the knife support!
The knife support is carried by two steel linear guides and is moved forward with the help of high-precision ball screw bearings. The hydraulic backlash compensation eliminates the play from the ball screw bearing. In this way, the low tolerance values can be ensured.
The control and drive system!
The drives which are responsible for the rotation of the plastic cylinder and the advance movement of the knife support, mutually check their positions, thus communicating with each other. This communication is realised with modern servo-drive technology and the respective control system.
The drive to rotate the cylinder acts directly on the cylinder via a gear unit. The drive of the knife support is connected to two precision gear units via toothed belts coupled to each other via a torsion-free shaft.
Backlash-free bearing of the billet clamping cylinder!
After the billet clamping cylinder has clamped the plastic cylinder which is a hollow plastic cylinder mounted on a mandrel, two other laterally arranged cylinders clamp the billet clamping cylinder to eliminate the play from its bearing. While a skiving mandrel is in the machine, the billet clamping cylinder is permanently under constant pressure.
Extremely sharp high-performance industrial knives!
Only extremely sharp high-performance knives allow the skiving of extremely thin films as well as of thick films which are exposed to heavy material stress. Hard metal elements soldered onto a carrier, which are ground and polished after soldering on, form the knife.
Skiving angle adjustment: In addition to the preset skiving angle which has proven itself for skiving PTFE, the adjustment of other skiving angles is also possible.
Pressure bar: The pressure bar creates almost constant properties of the billet before skiving. The high-polished pressure bar is mounted on the knife support and can be activated hydraulically.
Scribing knives: The scribing knives which can be optionally activated are provided for trimming the film to straighten the sides of the film. The scribing knives are mounted on the knife support and are pneumatically operated.
Reeling device: If requested, a reeling device can be supplied. This device is particularly adapted to the requirements of the film material skived on the skiving machine.
Knife grinding machine: With the high-precision grinding machine the high performance cutting knives can be re-ground.
Control, operation and accident prevention
Control system: A PLC which is installed in an externally ventilated control cabinet is used for the control of the machine. This sophisticated control system allows a simple operation during the setup of the machine and the further operation during skiving.
Operating devices of the film skiving machine: The skiving machine is operated by two operating units. A manual control unit is used for inserting and removing the billet with skiving mandrel into and from the machine and is equipped with all necessary functions.
The second operating unit, which can be swivelled over the machine, is used to set all the functions required for skiving the billet. These include, among others, the setting of the film thickness and the indication of fault messages. Furthermore, a button on the touch panel can be used to change the language. In this way, the language of the operator can be selected. A clearly arranged numeric keypad makes it easier to enter the desired values, which are shown on the touch panel display.
Operating the reeling device: If the reeling device is part of the scope of delivery, all operating functions of the reeling device are indicated on the second operating unit of the skiving machine, including the touch panel.
A small control panel for changing the film reel core is available in the area of the reeling position.
Accident protection: The machine is equipped with the required accident protection devices in accordance with the CE declaration of conformity and thus meets the prescribed safety standard.
Before delivery to the buyer, the skiving machine is checked in a comprehensive test run. If necessary, skiving tests with external material are also carried out.