Q&A
This section lists FAQs and our answers to them.
Inquiries about hard chrome plating
Q.01
●What is the difference between hard chrome plating and decorative chrome plating?
The plating film compositions of both plating methods are metallic chromium. However, decorative chrome plating is a plating method that aims at appearance and corrosion resistance, while hard chrome plating is a plating method that mainly aims at hardness and wear resistance. Therefore, decorative chrome plating does not need to have a thick film, while hard chrome plating needs a film thickness of at least 10 to 100 μm. Similarly, decorative chrome plating mostly has nickel plated as undercoating in order to increase corrosion resistance, while hard chrome plating is normally applied directly onto a substrate because it attaches greater importance to adhesion force.
Q.02 
●What is the difference between chrome plating and chromating?
Chromating is a chemical conversion coating applied onto zinc plating or zinc alloy plating. After zinc plating surfaces are activated, by immersing them into a chromate solution mainly consisting of hexavalent chromium, a chromate film will be deposited onto the zinc plating surfaces. Chromate films have excellent corrosion resistance because of their self-healing action. Chromate films used to be formed using hexavalent chromium plating solutions. However, because the films formed this way contain hexavalent chromium, in recent years, chromate films formed using trivalent chromium plating solutions are becoming mainstream because of environmental considerations.
Q.03
●Isn’t hexavalent chromium contained in hard chrome plating?
Hard chrome plating is electrolytically deposited as metallic chromium by reducing hexavalent chromium in a plating solution. This means that hexavalent chromium is not contained in hard chrome plating films. The results of demonstration experiments conducted by Technology Research Institute of Osaka Prefecture have revealed that hexavalent chromium does not dissolve from our plating. For details, refer to this PDF file.
Q.04

●Tell me about materials to which hard chrome plating can be applied.

Hard chrome plating can be applied to steel, copper, brass, stainless steel, aluminum, and titanium.
Q.05

●Tell me about the size of workpieces to which hard chrome plating can be applied.

The size of workpieces to which hard chrome plating can be applied differs according to materials, accuracy, specifications, and other conditions. For any inquiries about target workpieces, please send an inquiry form or phone us.
Q.06
●Can hard chrome plating be applied onto a complicated shape?
Hard chrome plating has poor throwing power and macrothrowing power, which means that it is very difficult to plate to a uniform thickness over a complex-shaped workpiece. However, Otec manufactures dedicated jigs to enable hard chrome plating to be applied to various shaped workpieces. For any inquiries about target workpieces, please send an inquiry form or phone us.
Q.07
●Can hard chrome plating be applied onto internal surfaces?
Yes, it is possible. We can also handle precision grinding, honing, and other machining for hollow cylindrical parts. However, restrictions apply to machining, depending on the relationship between the diameter and length. For any inquiries about target workpieces, please send an inquiry form or phone us.
Q.08
●Can hard chrome plating be applied onto castings?
This is technically possible, but we do not handle hard chrome plating on large castings at present. For hard chrome plating, anodic electrolysis must be performed in a plating bath to increase adhesion force. However, if a casting is subject to anodic electrolysis, free carbon will dissolve from the casting, causing plating defects such as pits and particles.
Q.09
●Can hard chrome plating be applied onto PVD-coated workpieces?
It is difficult to apply hard chrome plating directly onto PVD coatings. PVD films must be removed. The same applies to hard chrome plating on CVD coatings and thermal spray coatings.
Q.10
●Can chrome plating be removed and reapplied?
Chrome plating can be removed by grinding, immersion into hydrochloric acid, or anodic electrolysis in a plating solution, and then reapplied.
Q.11
●Can I get a plating sample?
Product samples are available for Tfe-Lok and Chroamor. For other trial products, please consult with us.
Q.12
●Can I request only heat treatment?
We accept heat treatment at temperatures up to 300ºC that aims to eliminate hydrogen from plating or remove stress from rolls.
Inquiries about Tfe-Lok
Q.01
●What is the difference between Teflon coating and Tfe-Lok?
Teflon coating is a surface treatment method that applies a membrane of polytetrafluoroethylene (PTFE) onto workpiece surfaces, while Tfe-Lok is a surface treatment method that is based on chrome plating and physically embeds PTFE into cracks on the chrome plating surface. For this reason, the film strength of Tfe-Lok is as high as that of chrome plating, providing excellent durability and wear resistance.
Q.02
●Can Tfe-Lok be reapplied?
Tfe-Lok can be reapplied by removing its film.
Q.03
●What is the plating thickness of Tfe-Lok?
The plating thickness of Tfe-Lok is 50 μm or more.
Q.04
●What is the surface roughness of Tfe-Lok?
The maximum surface roughness of Tfe-Lok is approximately 1.0S because its plating surface is etched when polytetrafluoroethylene (PTFE) is embedded.
Q.05
● Are there any types of Tfe-Lok surface condition?
Several types of Tfe-Lok surface condition are available, ranging from smoothness with a surface roughness of approximately 1.0S (as above) through to various types of satin finish specifications, any of which can be selected according to customer needs.
Q.06
●Tell me about the size of a workpiece that can be plated with Tfe-Lok.
The maximum size of a workpiece that can be Tfe-Lok plated using the current facilities is 3,500 mm in overall length. For any workpieces larger than the maximum limit, please consult with us separately.
Q.07
●Can Tfe-Lok be applied to complex-shaped workpieces?
Tfe-Lok can be applied to complex-shaped workpieces as long as chrome plating can be applied to them.
Q.08
●What is the hardness of Tfe-Lok?
The hardness of Tfe-Lok is approximately Hv850.
Q.09
●Is Tfe-Lok plating available from companies other than Otec?
Only Otec provides Tfe-Lok plating in Japan.
Q.10
●Can I get a Tfe-Lok sample?
We will send a Tfe-Lok sample at your request. Please send an inquiry form.
Q.11
●What is the heat resistance of Tfe-Lok?
The heat resistance of Tfe-Lok is below the melting point of PTFE (327ºC). For continued use, we recommend that Tfe-Lok be used around 250ºC.
Q.12
●Can I get detailed information about Tfe-Lok?
We will send catalogs and specific technical documents about Tfe-Lok at your request. Please send an inquiry form.
Q.13

●Is there any detailed data about compatibilities between Tfe-Lok and resins?

We have been internally investigating compatibilities between Tfe-Lok and various resins such as polypropylene (PP) and polyethylene (PE), but we do not present detailed data to customers. This is because there is a diverse range of environments where our customers use Tfe-Lok, such as temperature, resin types, and workpiece shapes, and the results of our experiments do not always agree with the results of Tfe-Lok uses in the customers’ working environments. For this reason, we recommend that trial testing be conducted in the environment where Tfe-Lok is actually used.
Inquiries about Chroamor
Q.01
●What kind of film does Chroamor form?
Chroamor is an alloy plating of chromium and carbon. Chroamor has an amorphous structure when a plating film is deposited, but the structure changes to a crystal structure when it is subject to heat treatment. When the structure changes to a crystal structure, the plating film hardens.
Q.02
●Can Chroamor be reapplied?
Chroamor can be reapplied by removing its film.
Q.03
●Tell me about the plating thickness of Chroamor.
The maximum plating thickness of Chroamor is 5 μm. It is possible to plate to a thickness exceeding 5 μm, but macrocracks will occur. Chroamor forms a crack-free and very hard film that provides sufficient wear resistance and corrosion resistance even when its thickness is 5 μm or less.
Q.04
●Is the film thickness of Chroamor uniform?
Chroamor forms a thin film with a thickness of 5 μm or less, which means that its film thickness is less uneven than other platings such as hard chrome plating. For this reason, Chroamor has been used for a variety of precision molds and other applications.
Q.05

●Can Chroamor be applied onto other surface treatments such as chrome plating?

Chroamor cannot be applied onto other surface treatments such as chrome plating.
Q.06

●Can Chroamor-plated workpieces be subject to abrasive machining?

Chroamor-plated workpieces cannot be subject to abrasive machining because its film is very thin.
Q.07
●What is the surface roughness of Chroamor?
Because Chroamor-plated workpieces cannot be subject to abrasive machining, its surface roughness is influenced by the surface roughness of its substrate. Rolls can be finished with a surface roughness of approximately 0.4S.
Q.08

●Tell me about the size of workpieces that can be plated with Chroamor.

We can handle workpieces that can be put in our plating bath with dimensions of 400 mm × 400 mm × 3,000 mm. For any workpieces larger than the maximum limit, please consult with us separately.
Q.09
●Is Chroamor plating available from companies other than Otec?
Only Otec provides Chroamor plating in the world.
Q.10
●Can I get a Chroamor sample?
We will send a Chroamor sample at your request. Please send an inquiry form.
Q.11
●Can I get detailed information about Chroamor?
We will send catalogs and specific technical documents about Chroamor at your request. Please send an inquiry form or phone us.
Q.12
●Tell me about the price and delivery time of Chroamor.
The price and delivery time of Chroamor differ according to the shape, accuracy, and other conditions of the workpiece to be plated. If you fill out an inquiry form, we will let you know the exact delivery time and price.
Inquiries about roll manufacturing
Q.01

●Tell me about the maximum size of rolls that you can machine in-house.

The maximum size of rolls that we can machine in-house is 600 mm diameter × 6,000 mm long. Rolls larger than the maximum size can be machined by our partner companies. For details, please send an inquiry form or phone us.
Q.02
●Can you manufacture rolls with a special internal structure?
Yes, we can. We have a track record in manufacturing a large number of precision rolls with a special structure, such as double wall coaxial rolls for forming films or sheets.
Q.03
●Can you repair damaged rolls?
We can repair rolls by replacing shafts, overlaying, or taking other measures. First, please let us look at the target roll and then let’s discuss how to repair it. However, depending on the condition of the roll, we may recommend replacing with a new roll.
Q.04
●Can you repair a knife roll?
We have much experience in repairing knife rolls. Please consult with us about any repair requests such as repairing blade edges and structural repairs.
Q.05
●Tell me about the precision level of rolls that you can machine.
The precision level of rolls that we can machine differs according to the size, shape, material, and other conditions of the roll to be machined. We have a track record in machining a large number of precision rolls in the order of 1/1,000 mm. Please consult with us, based on the actual drawings of the target roll.
Q.06
●Can you also engrave rolls?
We do not perform engraving in-house, but we can handle engraving in collaboration with our partner companies.