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Discover now our wide-ranged job offers and have a carreer at Dr. Dietrich Müller. We are looking for:

  • Wholesale and Foreign Trader
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PCIM Europe Nuremberg 2015

Thermally conductive pad: Thermipad TP 22715 with 15 W/mK

SPIE Smart Structures/NDE conference

Electronics & Components Hong Kong

Imports and exports of the electrical industry


InnoTrans Berlin

World Energy Engineering Congress Washington

Enova Paris

International Electric & Automation Show Bucharest

CFRP profiles

Energie Impulse Aachen

Water-jet cutting

 CWIEME in Berlin 2013

Coil Winding 2013

Thermiglue TL 23010

Coil Winding 2012

CWIEME Berlin 2012

Italian bobbin manufacturer

Working hours

NEC Birmingham UK

Advanced Engineering UK 2011

Clean Energy Expo Asia 2011

Contract 4S iPhone protectors


Electric Drives Production Conference

MOTEK 2011 and Bondexpo

IAA 2011

Norton TH

ArpaxX-Aramid Paper

Slot insulation material

Bern and public transport

Germany with great opportunities in the field of electric cars

Stamp parts from Valox for the lighting industry

Thermal management for LED – Applications

APTIV films are available as a new high performance materials

ArpaxX - push up the heat: Dr. Dietrich Müller GmbH

ZVEI: The Electrical Industry expects that the boom will continue in 2012

Lectures at the CWIEME Berlin 2011

CWIEME Berlin 2011: Dr. Dietrich Müller GmbH with a large product range

Increased Growth Forecast for the German Electrical Industry

Hannover Messe CoilTechnica:  A Good and Positive Response for Dr. Dietrich Müller

Delivery situation in Japan

FIEE: A resounding success for Dr. Dietrich Müller


Dr. Dietrich Müller: Punched parts made ​​of 3M VHB Tape

Dr. Dietrich Müller: Nomex® parts in self-adhesive version.

Dr. Müller GmbH CoilTechnica, Hannover.

Kapton MT in different varieties and Thermiflex

Dr. Müller GmbH: New product for the solar industry

Dr. Dietrich Müller registered as a UL – „Repackaged Recognized Components“ Company.

CWIEME Berlin 2010: Dr. Mueller in Ahlhorn

Dr. Mueller: High technology and innovation at one time in one venue

Dr. Müller GmbH continues its leadership as a supplier of Ultem films

Dr. Müller GmbH: New product line for films release

Dr. Müller proud of the opening of the Germany's first offshore wind park

Müller and Temac: Distribution agreement sealing materials

Get involved with the latest insulation product offerings at the Coil Winding 2010 – Dr. Müller GmbH


Direct request:

Enquiries from the United Kingdom:

Dr. Dietrich Mueller UK Limited

Tel    +44 7549 834830
Fax   +44 2476 996466


Enquiries from all other countries:

Tel: +49 4435 971010
Fax: +49 4435 971011

Let us know, which product you are
looking for and we will give you the
adress of the right distributor.



Rigidiso using instructions

The poor thermally conduction of the pressboards determines their processing. It is just ca. 1/200 of the steel. So heat accumulation occurs at the area being worked on, the temperature of the heat accumulation has to be below the thermal impact which would be dangerous for the pressboard.

This fact states the necessity to work with small chip cross sections. To enable machining economical anyways, it is important to seek for high cutting rates. Machines for light metal- and wood processing meet the requirements for processing pressboards to a large extent. The machines should have low-vibration to reach prefect cross sections.

Generally pressboards are treated dry, so without cooling. To cool the tools with compressed-air would be useful.

Chips which occur during machining (often in greater quantities) and the included dust are more than just stress for the operating staff; they are a risk for the bearing of the tool machines. The dust absorbs the oil, so dry running is possible.

Powerful evacuation systems as well as dustproof bearings and guide slide bearings are absolutely necessary because of that. Sometimes the glass fibre particles which were not evacuated with the dust during machining glass fibre reinforced pressboards, can cause itching on the skin. Closed clothing and the usage of skincare salves is effective for protection.

Failures during treatment of the pressboards can be avoided if the layer structure of the material is kept in mind before starting. The mechanical properties are influenced according to the layer direction.


Hard paper- and laminated fabric boards can be separated on a guillotine shear which is equipped with a holding-down device. It is important that the adjustment of the bottom blade is exact and it should be made at table height. The shear should not be used for sheet metal cuttings. The die clearance should be 0.1 mm.

To preheat the boards, especially these with a thickness of more than 1mm, at 100°C up to 120°C improves the quality at the cutting point in general and minimizes the possibility of breaking at the cutting point considerably. Lever shears can only be used for shearing-off because the cut pieces can show cracks starting at the cutting line.

Hole-punching and cutting

The quality of the cutting area depends on the condition of the tools, the Rigidiso pressboard model and the material thickness. The binder content of the hard paper boards, which varies in its rate for the different models, influences the suitability for die-cutting essentially. The low-resin quality (PF CP 201) is more suitable for die-cutting than the high-resin quality (PF CP 206).

The higher the material thickness is, the worse the cutting line is. It turned out that material to be cut with a board thickness of more than 1 mm should be preheated to 100°C directly before die-cutting. Thereby the pressboard elongates. Parts cut in this process minimizes by about ca. 0.2 mm up to 0.3 %. To get exact cuts an equal addition should be kept in mind when measuring the cutting tools.

Progressive- and combination dies with die set and resilient holding-down devices can be used as cutting tools. The space between the holding-down device and the matrices should be small, so lifting and possible pull apart of the single layers can be avoided during removal of the die.

A cutting clearance of 0.01 up to 0.03 x material thickness should be used. High holding-down device pressure minimizes the crack formation. The ridge width should be greater than they are when dealing with metal. The rule of thumb is: ridge width = ca. 1.0 – 1.05 times to the material thickness.

Sawing on circular saws

Boards up to a thickness of ca. 30mm can be sawn on circular saws with movable slides. To separate thicker boards the band-saw is more advantageous. To reach clear cuts the slide clearance of the blade to the material is essential even if the requirements include smooth and zero-clearance run. The sawing blade should be about ca. 5 mm greater on all sides than the material to be cut is. Unset and semi-polished HSS- and carbide tipped blades can be used for circular sawing blades. If sawing thicker boards frequently the carbide tipped sawing blades should be preferred.Blades with side set teeth are used in rare cases as their cutting areas need post-processing. The diameter of the sawing blades is 300 mm up to 350 mm in general. The blade thickness is 2 mm up to 4 mm. Blade thickness and tooth pitch depend on the thickness of the board which need to be cut. The thicker the board is, the thicker the sawing blade should be. The tooth pitch can be increased, but there should always be two teeth in mesh.A cutting speed of 4,000 m/min has to be sought for.




Sawing on band-saws

Separating the boards above thicknesses of 30 mm and contour cuttings of thinner boards are realised on band-saws. Therefore sawing blades with side set teeth have to be used. The common width of the sawing blade is 20 mm up to 30 mm, the thickness of the blade 1 mm and the tooth pitch 5 mm up to 7 mm.

Clearance angle α 30 – 40°
Rake angle γ 5- 8°

The cutting speed should be 50 m/min.

If slices and forces should be made of the boards, it is important to ensure that the edges do not break since especially hard paper tends to this. A sealing run made of the same material or to turn the edge from the opposite direction or breaking the edge find a remedy.

Nearly all turning operations are realised with carbide cuttings tools. Tools made of high-speed steel should only be used for occasional turning operations.


Holes up to a diameter of ca. 20 mm are drilled with a spiral drill. Deep holes with a diameter between 10 mm and 20 mm are drilled with twin-bladed tools. Holes with a diameter of more than 20 mm are realised with a circle cutter and gliding pins.

Because of the poor thermally conduction in the pressboard, temperatures which would put the tool as well as the workpiece at risk could occur while incorrect drilling. To avoid this, it should be ensured that the chips are removed smoothly and fast during drilling. Spiral drills with steep wire and wide, preferably polished flutes are well-suitable in this case. Furthermore repeated and fast venting facilitates the chip removal. When drilling the chip removal can be promoted if the chips are formed to twirls.

The drills should be 0.1 mm greater than the diameter of the required drilling. The acute angle of the drill influences the torsional, advance force and the quality of the drill hole. The lowest torsional and the lowest advance force are required for an acute angle of 100°. But then the edges at the holes slightly break. The lowest risk of breakings is determined at an acute angle of 50° up to 60°.

If it cannot be avoided to drill holes in slice direction, an accurate angle of 130° is practical. Fixed clamping protects the layers against separation. To drill a few holes spiral drills made of high-speed steel are suitable. If drilling more often, drills made of carbide metal are more economic. The cutting speed when using drills made of HSS is 50 m/min and of carbide metal it is 100 m up to 130 m/min. The advance can reach 0.4 mm/U.


High-speed machines are required for milling. For processing of pressboards especially the routers used in the timber industry which have spindle revolutions of 10,000 min-1 up to 20,000 min-1 are well suitable.

If tools like milling heads and slot mills from timber processing should be used on normal milling machines, it should kept in mind that the mills have at least four blades. The milling direction should always run in slice direction. If milling against slice direction, the edges at the outlet have to be protected against breaking.

The cutting speed on metal processing machines is 50 m/min at high-speed steel and 150 m/min at carbide metal tools. On routes 1,000 m/min are reached.

The advance is 0.5 – 0.8 mm/U. The tool angles are:

Rake angle γ 20°
Clearance angle α 20°


Winding in hard paper should only be used for fixed connections. Laminated fabric suits better for removable connections.

Winding in direction of the slices is not recommended.

During threading lubricants can be used. The threading tools have to have wide flutes.

Inner windings up to M2 and outer windings up to M3 can be cut without any problems. Windings with a diameter of more than 12 mm have to be pre- and re-cut.


The grinding destroys the high-resin surface of the pressboard. Because of that grinding is only done if small tolerances are required or as finishing at still existing cutting areas or for customising. Boards can be processed on rolling or band grinding machines. The grind speed is between 1,000 m/min and 2,000 m /min. The following granulations suit for both grinding lines and grinding discs:

Roughing 60
Smoothing 240


Our boards are delivered with pressed finish surfaces. Polishing is not needed. Only poor gloss can be reached by polishing on worn out areas. For pre-polishing nettle discs with suitable polish are used. Afterwards the re-polishing is realised with dry flannel discs. The peripheral speed of the discs should be ca. 30 m/s.


Before bonding the pressboards, the adhesive joint needs to be roughened. The two-component-epoxy resin adhesive well-suits for bonding. The quality of the adhesive joint is mainly determined by the evenly adhesive application and the evenly contact pressure.


Pressboards should be stored in closed rooms which are protected against humidity and pollution. The air humidity in the storage rooms should not exceed an air humidity of 65 % and a temperature of 35°C for long time. Boards with a thickness of 2 mm are preferably stored horizontal on a flat underlayer therefore two edges should be aligned. Boards with a thickness of more than 2 mm can also be stored standing. Please make sure that they are vertical. That avoids that boards of lower thicknesses bend and the cutting edge is damaged.