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topic 496

How to Electroform nickel -- Introduction to Electroforming


(1996)

Q. Hey, everyone! I'm very new to this (I won't say "green"; I'm not oxidized (or might we say "jaded") yet)... anyway, I was wondering ... I need a process that will allow me to electroform a >10 mil coating of nickel onto a conductive substrate, said coating to be mechanically finished. Can someone point me in the right direction? I'm not looking to take this job to someone's shop; I have my own equipment, but I need something like the Electroforming Society's old "how-to" sheets. Can someone tell me where I might find them on-line? Thanks!

Rich Martin
Seraphim Productions


(1996)

A. Hi, Rich. I think if you are patient in searching you should find some good technical articles from the Nickel Development Institute site as well as the many threads about electroforming here on finishing.com.

These days I don't see why you should need to mechanically finish after electroforming (although you may have your reasons). It should come out of the tank smooth and bright. Most electroformers use sulfamate nickel plating solutions, if that's a starting point, and very low amounts of brighteners or none. Maybe call up a supplier and ask for a sulphamate solution for electroforming to get started.

You may wish to review the excellent chapter on electroforming (and also the nickel plating chapter) of the Metal Finishing Guidebook.

Good luck.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



Seeking info on electroforming watch dial markers

(2000)

Q. Dear Sir,

In electroforming flat objects, I have a raw information that the metal substrate is specially textured, I guess it is for the ease of removal.

What specific metal is most suitable for this process? This metal substrate is then coated with photo sensitive coating and the image has to be transferred by a UV light exposure. After rinsing off excess photo resist, an electro deposition process will take place on the unmasked surface. What is the current density required if the product is about 1 inch diameter?

The purpose of my research is to acquire a technology of making the watch dial hour marker(gold and nickel) through electroforming. In our application after removing the product from the substrate, the bottom portion is sprayed with adhesive ready to stick on the watch dial face.

Thanks and looking forward for your prompt advice.

Lucas Arguillon
Process Engineering Manager - Philippines



Electroplating and Electroforming for Artists and Craftsmen

October 11, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hi,

I want to setup a nickel electroforming unit for watch hands in India. I tried so many people but couldn't get any info. I got some technology information from China that says I have to create a SS mandrel through graphic art film and photo resistive glue, than develop the mandrel >> washing >> acid activation >> washing >> dip into electroforming tank >> washing and than peel off using transfer sticker.

This info does not include chemical names, voltage, amps, flow rate, quantity of chemicals/gal, photo resistive chemical composition and any other know-how.

Can someone give me detailed know-how or suggest a book?

AMIT mittal
prepress - Kanpur, UP, India


October 11, 2012

A. Hi Mittal. We appended your inquiry to a thread which should answer it. The "Electroplating Engineering Handbook" [link is to product info at Amazon] also has a great chapter on electroforming with over a hundred references. But it is obviously hard to proceed from no prior knowledge, so it will probably go faster if you can retain a consultant or at least get help from a supplier. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


October 17, 2012

A. Contact the Institute of Metal Finishing in Birmingham, UK. They have a very good education course on electroforming that can be done by distance learning.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK



Current density for Nickel electroforming?

(2000)

Q. Hi,

I have a Nickel Sulphamate process and am trying to electroform surface patterned photoresist structures. My process works fine for non-patterned photoresist, but with patterned photoresist the electroform peels/pops away from the substrate during electroform. My guess is that the current density ramp is wrong. Could anyone give me an idea of typical current density ramps for CD manufacture. At the moment am using 17 ASF for 15 mins, ramp to 60 ASF in 1 min and plate for 5 hours.

Regards

Mike Miller
- Quebec City


(2000)

A. It depends very much on the agitation, Mike. With minimal agitation 60 ASF is probably too high. With good agitation it's probably no problem at all. You might want to investigate a real-time stress monitor or, at the very least, "stress tabs" (a modified hull cell panel coated with resist on one side and serrated like a comb so you can see the stress at different ASF)

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2000)

A. Hey Mike,

First the photoresist, some resists adhere better to a oxide than to clean metal (I know you don't want an active mandrel but the oxide layer needs to be even) so you must be sure that the surface to be plated is free of trace resist (easier to see with copper than nickel but can be done). Resists have a lot of factors to get right. (A balance of F-stop number and range, development break point, resist adhesion, to control side wall softening and leaking and good optics to insure sharp/clean features (good film density, complete vacuum, and proper light source.)

Next the bath/deposit stresses must be mildly compressive to hug the mandrel. As the deposit gets thicker this is more important. Measure the stress at the CCD you are using and remember that a patterned area (lines in the photoresist) plate at many different CCD's all at the same time with the finest lines plating at the highest CCD.

Regards,

Fred Mueller, CEF
- Royersford, Pennsylvania


(2000)

Mike Miller:

I'm interested in the photoresist used in the process described in his letter. How thick can this resist be applied and "cured"? The application I have in mind would require a 20 mil thickness.

Steve Hudson
- Huntsville, Alabama


(2000)

Q. Ted, please give some more info about the "stress tabs".

sara michaeli
sara michaeli signature 
Sara Michaeli
chemical process supplier
Tel-Aviv, Israel



(2000)

A. Hi Sara. "Stress-tabs" are offered by Larry King Co., 13708 250th St., Rosedale, NY 11422. Whether the name is a trademark I don't know, because I've only heard it verbally and second-hand. Likewise, whether there are competitive products or the idea is patented, I don't know.

In any event, they are Hull Cell panels which are coated with a resist on the back side so that only the front side gets plated. They are also notched so they look like a hair comb. The result is that the individual tabs plate only on the front, and then curl in if tensilely stressed or curl out if compressively stressed, in proportion to the magnitude of the stress in the plating; you can interpret them to determine, for example, what current density you should plate at in order to achieve minimum stress with the solution chemistry you have.

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



Looking for the method for separation of Nickel electroform from Brass substrate

June 20, 2012

Q. I am a undergraduate student working on a project where I should conduct nickel electroforming process on brass substrate.

Brass substrate has micro-scale patterns on it and it should be replicated via nickel electroforming process.

Prior to the electroforming process, I passivated the brass substrate with oxide layer to prevent diffusion between brass and nickel.

I did a couple of experiments and found it difficult to separate electroformed nickel from brass substrate with maintaining reasonable flatness.

Anyhow, the main factor I should focus on is the flatness of electroformed nickel.

Is there any novel method for this?

Any comments would be appreciated.

Taekyung Kim
Computer - Seoul, South Korea

July 2, 2012

A. Electroforming is not a simple case of depositing a metal onto a mandrel and then removing it as a perfect shape. The mandrel needs to be designed correctly so that the electroform can be removed - that is, there needs to a draught angle on the mandrel. Secondly, the mandrel must be adequately passivated; brass can be passivated by a tenacious layer of copper sulphide, so dip your mandrel in a solution of sodium sulphide (50-100 g/l) or better still, sodium metabisulphite (200-220 g/l) and leave it for 5-8 minutes. Alternatively deposit a thin layer of bright nickel onto the brass mandrel and then passivate it. Nickel does not easily adhere to another nickel surface, especially if it is bright, but the extra passivate gives it an even better chance of separating.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

----
Ed. note: For more info on separating electroforms from mandrels, you may wish to view letter 42447, "Electroforms are sticking to cathode/mandrels"




Can't Remove Oxidation on Electroforming Mandrel

March 27, 2014

Q. Hello finishers,

I work at a Nickel electroforming factory which specializes in growing nickel products from a mandrel made of nickel also.

Previously we were able to achieve a life cycle in the range of 50 grows for a nickel mandrel, but recently government has been enforcing policies to restrict our daily water use.

Now the average life cycle for a mandrel has dropped to about 20-30 grows. Main defects we are finding are a white or yellowish oxidation which the image then transfers to the final product. The oxidation does not get removed during any cleaning process or acid soaks.

After each nickel grow we clean tools using anodic electroclean, neutralize with acid, then passivate with potassium dichromate.

If anyone could provide some insight into what causes this visible oxidation on nickel mandrels and also if there is a product out there that can remove it.

Thanks.

Mark Stanfield
R&D Manager - Shenzhen, China



How to make nickel perforated textile screens

June 5, 2014

Q. Rregarding the nickel perforated screen for textile printing.

Which method or chemical composition will be better to get the high open area in finer mesh for textile rotary screen manufacturing ?

Ajay Prajapati
plating shop employee - Ahmedabad, Gujarat, India


June 2014

A. Hi Ajay. Nickel electroforming, probably from a nickel sulphamate plating bath, is the way forward.

Picture this: start with one perforated screen made of whatever material you wish, perforated by whatever technology you wish. Passivate it so plating won't stick too well to it, then do a heavy plating of sulphamate nickel on one side only. Separate the plating from the substrate (mandrel) and use it as the screen; do it again and again.

Luck and Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



Process for electroforming metal stickers

November 12, 2014

Q. l want to learn the electroforming of metal stickers process: how many processes, which chemicals are used, how many times dried -- as an important knowledge,

Is there any sheet or book about this process?
What is the important part of electroforming metal stickers?
Can I find someone to help me with this Project?

sel ban
- turkey,istanbul



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