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Tool Coatings ( PVD )

Zahnrad Kopf

Diamond
Joined
Apr 5, 2010
Location
Tropic of Milwaukee
Is there anyone here with in-depth applications knowledge and experience with PVD coatings? I want to have some tools coated and am running into a hard wall of salesman horse puckey.

Bottom line is that the Gear Shaper Cutters that I design and make in-house have gotten to a point that we are no longer using them solely for prototyping designs and small runs. The capability has become 20x more popular than I ever dreamed it would. That is fantastic, but what comes with that is the reality that now we are being asked to do longer runs and larger quantities with them.

Suddenly, tool life becomes an issue. And for all the work that goes into an Asymmetrical Tooth Form tool (or Skip Tooth / Skip Space tool ) from designing it, drawing it, to purchasing the carbide blank, to manufacturing it, and then using it ( not to mention all the tool holding to accommodate them ), I don't want to have to make more than what is required to run the actual job just to have an extra on hand in case one decides to break or one of us has a bozo moment and runs it without oil or too fast.

So, I know I want to have them coated, but what I do not know is which coating to use. Some coatings don't play well with some materials. And some coatings do not like carbide, I have been told. At the price point that it appears we are working it, cost is not even a concern. We are talking about possibly a $10 difference in cost to us.

However, if one coating is going to be demonstrably better than another, I want to know and choose that one...

Tools are solid carbide. Parts are commonly alloy steels ranging from 35 - 50 HRC, but Martensitic Stainless is not uncommon. Aluminum and Cast Iron happen occasionally.

Part of the issue I am running into is that salesmen are making stupid claims without having a clue about what gear shaping even is, much less the cutting forces involved versus milling or turning. The best comparison I have been able to come up with is a broach, but then then don't know what to say after that.

Right now, I am leaning toward AlCrN ( Aluminum Chromium Nitride ) but if there is a better choice, I would definitely like to know.

Thanks.
 
I do t know about your application but for cutters I've always had good luck with AlTiCN...not good with aluminum. For aluminum I'd go with ZrN coated.
 
In '92 they were in Mt. Clemens, MI. We got some end mills coated with their Titanium Carbonitride. Success!
I guess they were sold:
Gear Cutting << Oerlikon Balzers USA

I'm working completely in the dark, here so far... However, TiCN is second on the list right now. I did email ( two addresses ) and called ( two voicemails ) Oerlikon, but have not heard back yet.

It's really discouraging and pathetic the line of BS and stupidity that I'm being fed by some of these sales people...

One is trying to tell me that they can guarantee 50% more tool life. How do you do that on something that you have ZERO prior data on? I told him I would commit immediately if he was willing to sign paperwork saying as much and told him that a single cutter costs $5K. ( it doesn't, but what the hey ) He must have had a meeting to go to because his replies suddenly stopped...

:rolleyes5:
 
I'm working completely in the dark, here so far... However, TiCN is second on the list right now. I did email ( two addresses ) and called ( two voicemails ) Oerlikon, but have not heard back yet.

It's really discouraging and pathetic the line of BS and stupidity that I'm being fed by some of these sales people...

One is trying to tell me that they can guarantee 50% more tool life. How do you do that on something that you have ZERO prior data on? I told him I would commit immediately if he was willing to sign paperwork saying as much and told him that a single cutter costs $5K. ( it doesn't, but what the hey ) He must have had a meeting to go to because his replies suddenly stopped...

:rolleyes5:

TiCN is a great coating as well. And it behaves with aluminium.
 
Both actually...weird right
And somewhat different. Welcome to the world of carbide coatings. :)
Brazed or free pieces of carbide? Even at the low temp of PVD some can't be put on brazed tooling and/or special braze must be used.
Then there is edge prep...... speeds are slow, you may be microchipping the edge in the first few passes. A .001/.002 hone may help... or maybe not.
Seems weird to dull a tool to make it last longer. This can be easily done with a brush.
Production gear cutting on all older machines with carbide has always been a problem due to surface footage.

Also I'd guess that this is an EDM form. Grinding the top last helps a bit here and flanks need a lot of very fine finish passes.
Speed is slow, carbide likes higher side clear angles than HSS. Not sure the wear or failure mode without pics of a few cycles and many cycles so I'm kind of shooting in the dark.
Bob
(just two cents or less from the peanut gallery side)
 
And somewhat different. Welcome to the world of carbide coatings. :)
Brazed or free pieces of carbide? Even at the low temp of PVD some can't be put on brazed tooling and/or special braze must be used.
Then there is edge prep...... speeds are slow, you may be microchipping the edge in the first few passes. A .001 hone may help.
Also I'd guess that this is an EDM form. Grinding the top last helps a bit here and flanks need a lot of very fine finish passes.
Bob



I could easily have sent this via private email, as we are already corresponding...


You know... it occurs to me that I am a COMPLETE and utter moron... We are buying our carbide from someone with decades in the industry, who also knows a thing or two about coatings. But would I be smart enough to think to call him directly and ask these questions? Noooooo... I have to be so stupid as to email every Joe Shite, the rag-man in the country, looking for information...

Some times I am my own worst enemy.

CarbideBob, please accept my apologies. I should have simply called. Some times I can be obtuse. Since we are here anyway, would you mind weighing in and recommending a coating for our needs?

Thank you, Sir.

EDIT -

I just not saw your last response. :) Yes, they will mostly be brazed in place. I'm using the same flux and silver braze as you. There will be some times where it will be possible that we might send just the actual carbide tool, though.

There have been failures, but this effort is not to address those. Most of those were my fault. Plain and simple. Most times when there is a failure, it is from too much pressure on a small profile, created by not noticing and then sharpening in time. Usually, it is a fracture leading to chipping, vertically along the "teeth", taking out the "tip" area for a distance along it, requiring much more sharpening than normal to get past it and get back to a good area of cutting tool.

Again, those are most commonly my own fault. I do not ( and can not ) expect coating to correct stupidity.

/EDIT
 
Always good to have a lot of people involved and opinions. No apology needed ever.
Talking to carbide coating salespeople must be interesting, fun, and confusing.
I think putting it out a great idea. I have thoughts, others have thoughts.
The more the better. You can pick up the phone and call me anytime but maybe this gets a wider audience and many other viewpoints. That has to be all good.
I look forward to any suggestions by anyone. I know a very few things , others here know things I do not and sure as shit have kicked my dick in the dirt.... That makes us a community.
Posting this here a very good idea.

What really, really sucks and will keep me up at night is that it is not working so well as I supplied that carbide.
That just simply blows, I was worried about this issue and sure as hell here it is.
Zahnrad , I do not mind it being out front for all to see.
Bob
 
Bob - no, no... this is not a problem, really. Seriously. It has only happened a few times, and it is MORE than likely my fault. I am convinced of that. The carbide you have been providing has been performing VERY well.

In point of fact, the occurrence was MUCH MORE common of a problem when I was using HSS. That is a discussion for a different thread, though. :) Your carbide has been wonderful, and has made accomplishing our goals easier.

It has not happened at all in the last 8 or 10 cutters. I attribute that to being more mindful of cutter wear, the new sharpening fixture we built ( allowing a much more refined cutting edge ), and also having taken some pains to refine the cutter profile creation ( more finish passes ).

Your carbide is fine. Rest assured.
 
Part of the issue I am running into is that salesmen are making stupid claims without having a clue about what gear shaping even is, much less the cutting forces involved versus milling or turning.
Right now, I am leaning toward AlCrN ( Aluminum Chromium Nitride ) but if there is a better choice, I would definitely like to know.

Thanks.

The aluminum chromium nitride coating is the most recent design that Gleason is providing . This may be a situation were you need to take advantage of a larger company's research.

Gleason is using Balzers equipment for their coating service.

Gleason Expands Advanced Coatings Facility

There has been a trend over the last 10 or more years for the smaller tool coating companies to abandon their own in house process development and coating equipment design and buy the ready made equipment with the built in coating process library. These companies have transitioned from being a engineering operation to being a business. With that transition there has been a loss of skilled staff who are knowledgeable as to what the appropriate coating design should be for a particular application. I suspect that the salesmen that you have dealt with fit that description.

If you want to know what the current best commercially available coating design is for gear shaper tooling you will need to deal with Balzers or one of the other coating companies that maintain a research and development staff.

Balzers has made recommendations in the past (2004). This article was promoting the use of a titanium aluminum nitride coating. The current aluminum chromium nitride coating is a newer design with improved properties.

PVD Coatings for Improved Gear Production | Gear Solutions Magazine Your Resource to the Gear Industry

The coating choice may be limited If you plan on reworking the coated carbide tooling when it become dull. There may not be a chemical etching processes available or it may not be cost effective for some of the multi layer coatings.
 
< snip a lot of good information >

Gleason is using Balzers equipment for their coating service.

Oerlikon Balzers will be here shortly. Color me impressed with the response, so far. ( given how small time we are in comparison and proposed usage ) Will update once I know more.



Speed is slow, carbide likes higher side clear angles than HSS.

This highlighted in my head this morning. Thank you for writing that out, CB. I knew this, but completely glossed over it during this process. I got caught up in how things had always been done before, and using that as a guideline to how to proceed with my efforts. That was stupid. What I am doing is not earth shattering, but it is different enough that I should have not done that.

I do have the ability to control that relief, since I am the one designing the tools. Right now, side clearances run between 0.5° and 1.5° depending on many different factors. I think I may just experiment with much higher than normal side clearances in an effort to contrast and compare the effects and results.

There is a fine line to walk for me in doing so, but can you recommend a side clearance that you think might be a good middle road with this C2 micrograin?

Thanks CB! Very much appreciated.
 
Double where you are.
Normally in steel I design around 3 degrees after feed (side feed not a concern in a broach), sometimes more , sometimes less as it depends on material springback on the heel side once the shear has formed.
If in early cutting you have signs on the flank before signs on the top or edge you are lacking clear.
One has to check a cutting tool often to know what is going on. This means first few cuts or even just one, and a bunch of checks with a magnifying glass or other as it gradually dies.
People bring me burned/ broken up tools and ask, I have to tell them I have no idea, it is dead and what I need to see is in your chipshoot.
Looking at the chips is also very important. That is the first thing I gather off a machine, several little bags of the chips during the run. Was there a change, how did they change and why?
The chips talk to you as much as visual on the cutting tool. Maybe more.

Aluminum or other soft cutting and double that clear again.
Bob
 
Update -

Oerlikon Balzers stopped by yesterday. WHAT A DIFFERENCE! The rep has worked in the gear industry before, so understood my concerns, innately. We were already far and away better than the majority of sales twats I'd been dealing with. After some brief conversation and back and forth of questions, he started discussing some aspects of the cutters that no one but CarbideBob had previously thought to ask. ( CarbideBob is who we purchase our blanks from and as such we have had numerous background conversations about what we are doing, here )

Bottom line is that I came away from the meeting educated about our choices, educated about some things we will need to watch out for in the future, and how best to move forward. I'm not exactly known for tolerating salesmen very well. I tend to take their bs in a personal manner and often as a challenge, and often end up politely ( or not ) thanking them for their time and walking them out once their bs has been exposed as such.

This time, I was happy for the visit. Well done, Oerlikon Balzers. Well done!

I am still going to speak with Swiss Tek because they are local and a friend of a friend that comes recommended. I may even have both do some coating in effort to get some experience with comparisons.

I'll update how things shake out, later in the process. Thank you to all that weighed in. ( especially CB! )
 
lots of pitfalls

Oh boy, I've been down this road a few times. More important than process is mindset within the coating facility. Most of the product they handle is in bulk, drill bits, end mills, die pins, etc. I was witness to the near destruction of new, shaper cutters processed by a regional facility. There was no comprehension of non contact handling.

In another lifetime I interviewed at Pfauter-Maag/Gleason in Loves Park for cutter engineering and sales. Impressive investment in PVD technology. They now get all my sharpen & coat business for specialty cutters. Removal of the sharpening grind burr prior to coat is uniquely critical.
 








 
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