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WerkzeugTechnik

Technologie - System - Logistik

Technical magazine for cutting tools and measurement in the manufacturing

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ISSN Nr. 0997 - 6981www.werkzeug-technik.com

24 August 2018Nr. 169

Due to the increase of the

special demands, PLATIT

decided to specialize its team

in Riaz, Switzerland to engineer

and produce special machines.

Tibor Cselle, Chris Galamand, Dominik Blösch - PLATIT AG, Selzach-Riaz, Switzerland

Dedicated Coating Systems for Special Applications

– Cutting Tools: manufacturers of largecutting tools like broaches & sawblades

– Aerospace: anti-abrasion, anti-erosionhard coatings, scratch resistance coat-ings

– Plastic injection: extra smooth coatingsfor corrosion and scratch protection &lubricant films for moving elementswith minimum lubrication and tighttolerances

– Medical: bio compatible coatings fordental components and medicaldevicesFrom our portfolio, the following tech-

nologies were already implemented anddelivered:– ARC – in DC & pulsed modes– Sputtering – in DC, pulsed & HiPIMS

(High-power impulse magnetron sput-tering) modes and

– PECVD (Plasma Enhanced ChemicalVapor Deposition) modeThis paper introduces interesting and

sophisticated special systems, whichrequire special machine designs, holders,handlings and coatings for: – broaches,– saw bands,– saw blades, and– machine components.

Inclined system for coating

band sawsSaw bands are wound up and coated

in coils. In order to avoid overbending,the coils must be wound up with a cer-tain minimum inside diameter and formaximum productivity with a maximumoutside diameter. The system was builtfor the company Wikus (Spangenberg,DE, Fig. 2) in our plant in Sumperk,Czech Republic. It can span saw bandcoils with an outside diameter of up to1.4 m, which can be used to coat sawbands up to a length of approx. 400 m inone batch.

The system uses three standard rotat-ing LARC® [1] cathodes covering a coat-ing height of 440 mm. The wound sawband coil spins in front of the cathodes. Ifboth the cathodes and the coil were per-pendicular, a non-constant layer thick-ness distribution would arise dependingon the coil radius. Therefore, the carryingturntable of the coil was tilted. The incli-nation of the coil causes a distanceincrease between the coil and the cath-odes, which equals the dissimilar circum-ferential speed along the radius of the

COATING //////////////////////

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C oatings for cutting tools are usuallyproduced in standard equipment.

The typical coating chambers offer coat-ing volumes of ~ø300 x 300 to ~ø700x700mm.

PLATIT’s main business runs with thestandard machines of the series 11 [1],which covers the entire spectrum of coat-ing plants:– π111: a small system with ø355x440

coating volume,– π411: a medium sized unit with ø500 x

440 mm coating volume and– PL1011 and π1511: large systems with

ø700 x 700 mm coating volume.During the last two decades PLATIT

successfully grew a large worldwide net-work of customers, who came to PLATITwith their special demands. Due to theincrease of these special demands,PLATIT decided to specialize its team inRiaz, Switzerland to engineer and pro-duce special machines. The engineersand technicians are specialized in:– concept development– advice & consultation– mechanical & electrical equipment

design– customer specific programming– manufacturing with a local network of

Swiss companies– factory acceptance test and commis-

sioning at customers’ facilities– machine and process support & spare

parts.According to the new concept, PLATIT

approaches large companies as well asSMEs worldwide.

Several systems have already beendeveloped, produced and delivered tothe following sectors:

Fig. 1: Coated big broaches.

(with coating volume ø700 mm x 700 mm) (Fig. 6a), [1], [4]. The hat isplaced on the top of the standard cham-ber, a simple tube. This can be used tocharge broaches with twice the length(1.4 m). In the first batch half of thebroach’s length is coated. Thereafter, thebroach is turned by 180° to complete theother half in the second batch. Of course,the hat solution is slow because it dou-bles process time, but it is cost effective.

With the extremely long broaches, wehave to break with the principle; “Thecathodes must be longer than the coat-able height”. Extremely long cathodeswould be extremely expensive.

The distances between the saw bladesdetermine the layer thickness distribu-tion in the «depth» of the saw blade (Fig.5), which is only important for HSS sawblades. They are usually only regroundand not recoated. After regrinding thelayer only remains on the side surfaces ofthe saw blade, contributing to a smallincrease of tool life. It speaks in favor ofrecoating reground saw blades, a per-spective for future applications.

Machines for coating broaches

Several projects for broaches wererealized by PLATIT with the “hat solu-tion” of the standard machine PL1001

COATING //////////////////////

coil. In the meantime, after its commis-sioning, the plant has nearly coated 7-digit meter numbers of saw bands. Byusing dedicated coatings, enormous pro-ductivity increases have been achieved(Fig. 3).

Coating plants with a large

chamber diameter for coating

saw blades

In order to increase productivity whencoating saw blades, special substrate car-riers are built up, which enable over-lapped clamping of the tools. In the plantPL2001 (Fig. 4), which PLATIT built with1.15 m coatable diameter for the com-pany TRU-CUT (Brunswick, Ohio, USA[4]), more than 1000 saw blades, with adiameter of 160 mm, are coated in onebatch. At 450 mm diameter, there’s roomfor 172 tools.

The diameter of the chamber and thusthe number of coatable tools per batchcan be increased further. It is thanks tothe fact that the coating only matters onthe outer edge of the tools (i.e. on thesaw teeth) and the carousel (the rotatingtool carrier).

3 / Werkzeug Technik / NN° 169 / 24 August 2018

Fig. 2: π603 coating machine for saw bandsUser: Wikus, Spangenberg, Germany.

Fig. 3: Development of dedicatedcoatings for sawing in stainless, austenitic steelWork piece material: X6CrNiMoTi17-12-2 – 1.4571D-work piece: 300 mm. Source: Wikus, Spangenberg, Germany.

height of 1.8 m. The coating thicknessdistribution can be opimized with thehelp of more cathodes.

This year there is a machine in the pro-ject stage, which also receives 2.5 m longbroaches and can coat 2 m workinglength on the tools. We use six verticallyand horizontally offset cathodes (see Fig. 6c).

COATING //////////////////////

Because of the enormous masses ofbroaches, the carousel (tool carrier) mustbe guided on a track that is sunk into thefundament (see Fig. 6b).

According to the principle of theturnkey solutions from PLATIT, thesystem will be supplied with an adaptedsingle-chamber cleaning system [1].

Machine for Coating

ComponentsMany moving parts in the machinery

and automotive industries do not needextra hard coatings. But they must beextremely smooth and have to show verylow coefficients of friction.

For a smooth adhesion layer, theHIPIMS sputtering method is suitable[6]. In the plant PL1011-Hybrid (Fig. 7), avery thin (~200 nm) CrN layer is sput-tered pulsed, as a ground layer.

After deposition of the adhesive layer,the shutters of the cathodes will beclosed and a DLC (Diamond Like Coat-ing) layer will be formed by a PECVD

PLATIT supplied the company Genta(Torino, Italy) with the PL2500 (Fig. 6b).It can pick up broaches up to a length of2.5 m and coat up to 1.8 m workinglength. The machine works with fourcathodes, two on top of each other on theopposite sides of the chamber. They eachcoat 700 mm, resulting in 400 mm missing for direct coverage of the total

4 / Werkzeug Technik / NN° 169 / 24 August 2018

Fig. 4: PL2001 coating machine for saw bladesUser: TRU-CUT, Brunswick, Ohio, USA.

Fig. 5: Reduction of the layer thickness when coating saw bladesMeasured by saw blades D = 280 mmat d = 25mm distance between twosaw blades.

COATING //////////////////////

process. The extremely smooth DLC2

(Sa<20 nm) layer is deposited as silicondoped amorphous carbon with hydro-gen; a-C: H: Si [1].

This combination of PVD and DLCcoatings offers very good adhesion,smoothest surface finish with good hard-ness. Their main applications for thisprocess are– high quality machine components,

medical devices, aerospace compo-nents, as well as

– cutting tools for composite materialswith affinity for built up edges, and

– stamps, dies, and cutting tools.

Outlook

Especially for large tools, the standardcoating systems are limited. Even thecoating of components in large quantitiesrequires special machines.

PLATIT set up an independent pro-duction facility for special equipment.The production unit, managed byextremely experienced specialists, plansand manufactures these special systemsin coordination with users, according tothe specific requirements, includingdesign, planning, production and com-missioning.

The focus is on special equipment for:– broaches,– saw blades,– hobs, and– machine components with special

requirements,– embossing rolls, and punches.

(16918-317)

5 / Werkzeug Technik / NN° 169 / 24 August 2018

Fig. 7: PL1011-Hybrid coating plant for components in the automotive industryUser: Fullandi, Shenzhen, China

References

[1] CompendiumPLATIT AG, Selzach, 60th edition, 9/2018

[2] Cselle, T.: Inclined LARC coating system - Dedicated for saw bandIOT Surface Kolloquium, Aachen, 12/2007

[3] Coating unit for big saw bladeswww.trucutsaw.com

[4] Coating unit for broaches with “hat”www.metalestalki.com

[5] HIPIMS technologywww.nano4energy.eu

Fig. 6: Coating equipment for broachesA: PL1400 with hat at Metallestalki, Bilbao, SpainB: PL2500 at Genta, Torino, ItalyC: PL2511 project with 6 cathodes