plating tolerance
plating tolerance
(OP)
We typically specify zinc plating according to ASTM B633 including the thickness of the plating. We do not specify a tolerance for the thickness and I haven't been able to find anything that indicates what "standard" tolerances are for zinc electroplating.
Does anybody have any standards or experience with this you would be willing to share?
Thanks!!
Does anybody have any standards or experience with this you would be willing to share?
Thanks!!





RE: plating tolerance
It depends on the type of plating and material.
A Google search shows a lot of data on this.
http://www.finishing.com/224/09.shtml
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)
RE: plating tolerance
Heckler
Sr. Mechanical Engineer
SWx 2007 SP 3.0 & Pro/E 2001
XP Pro SP2.0 P4 3.6 GHz, 1GB RAM
NVIDIA Quadro FX 1400
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(In reference to David Beckham) "He can't kick with his left foot, he can't tackle, he can't head the ball and he doesn't score many goals. Apart from that, he's all right." -- George Best
RE: plating tolerance
http://techplate.com/tpeprice.htm
RE: plating tolerance
What would you do if you need to manufacture a plated 3A or 3B class thread on bolt or on tnternal thread? There is no way to do it without giving the thread tolerances before plating and after plating. The pre-plated tolerances dictate the desired plating tolerances. From my experience the tolerances for Zinc electorplating a tolerance of 0.003 to 0.0004 mm is common. For internal thread or holes an electrode inside the thread/hole may be necessary.
For example QQ-Z-325C federal standard dicatates 0.005 mm for Class III and 0.013 for Class II. These are minimum plated thickness insure the 12/96 hours at salt spray bath. Therefore, you have to give tolerances to the plating if you manufacture parts such as class 3A and 3B bolts and threads.
RE: plating tolerance
However, I often see 'Dimensions apply after plating' as part of the plating note.
Probably not much help, sorry.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
We have some parts that have some tight tolerances so this can become very critical and chops away at the tolerances afforded to our manufacturing guys.
The link posted by ctopher seems to indicate to me that +/- .00015" on plating thickness is reasonable but I don't know if this is actually easily produced using standard (i.e. low cost) plating methods.
RE: plating tolerance
Like I mention above.....find a good plater and talk with them about their process and ask good questions.
Heckler
Sr. Mechanical Engineer
SWx 2007 SP 3.0 & Pro/E 2001
XP Pro SP2.0 P4 3.6 GHz, 1GB RAM
NVIDIA Quadro FX 1400
o
_`\(,_
(_)/ (_)
(In reference to David Beckham) "He can't kick with his left foot, he can't tackle, he can't head the ball and he doesn't score many goals. Apart from that, he's all right." -- George Best
RE: plating tolerance
Every company I have been with, the outcome was to leave off the tol on the dwg and call out the appropriate spec with type of plating.
I suggest calling your plater and ask them what their recommendation is.
My experience.
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)
RE: plating tolerance
There is no way to have a "standard variation" for plating thickness without also defining a standard test coupon.
I agree with the others that the finished part has its necessary tolerances defined by the part design engineer, and that the tolerances apply after plating.
A good plater will have a decent idea of what thickness variation to expect based on geometry and topography, and will work with you to suggest changes to the unplated part so that the finished part will be what you need.
A bad plater will feed you a line of BS about "standard plating thickness tolerances".
RE: plating tolerance
Finding a good supplier and keeping communications going with them has proven beneficial to the results. The trick then becomes keeping them from being cut out as a result of someone elses cost reduction efforts (unless the alternate source proves equally as capable)
Regards,
RE: plating tolerance
RE: plating tolerance
For certain critical applications I suppose you may need more, is this what the OP is asking about?
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group
RE: plating tolerance
I don't see "Dimensions apply after plating/finishing" as being a process. It's just a clarification of requirements.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
Heckler
Sr. Mechanical Engineer
SWx 2007 SP 3.0 & Pro/E 2001
XP Pro SP2.0 P4 3.6 GHz, 1GB RAM
NVIDIA Quadro FX 1400
o
_`\(,_
(_)/ (_)
(In reference to David Beckham) "He can't kick with his left foot, he can't tackle, he can't head the ball and he doesn't score many goals. Apart from that, he's all right." -- George Best
RE: plating tolerance
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group
RE: plating tolerance
I would argue that without a thickness spec defined by design engineers and complete dimensional requirements for the final part how can the part be produced without someone making an assumption at some point? Granted the plating thickness is typically very small but can and has created problems for us.
All drawings do contain the note "dimensions and tolerances apply after plating or painting unless otherwise specified".
Of course I could be way off base here - wouldn't be the first time.
We manufacture most parts in house and send out for plating/painting when required. The only information on drawings are the final requirements and thickness of plating/painting so in process stuff is up to the manufacturing guys - they can do whatever so long as the end result meets spec.
RE: plating tolerance
To meet the salt spray test maybe just specify minimum thickness.
I'm not familiar with ASTM B633 but I just looked at the UK defence standard we used to use in UK http://www.dstan.mod.uk/data/03/020/00000300.pdf and it actually says that you should specify the thickness of the plating on drawing (or in PO etc), so I was doing it wrong for a while. However, it does only give minimum thickness where it talks about thickness for different applications, not a range/tolerance.
So I’d take a look at ASTM B633 and assuming it’s similar to the Def Stan I’d put a minimum plating thickness as required to meet whatever your salt spray test is. I’d also still include the ‘dimension apply after plating’ note (sorry fcsuper, have to agree to disagree this time).
I’d still say it’s up to manufacturing to determine the actual machined dimensions/tols in coordination with the plating vendor but they would now have the minimum plating thickness as a start point.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
Also, If you model the part, model it minus the plating for machining purposes. Some parts are machined after some plating. If the parts plating has to be precise for fit, make it a separate part to include plating, if needed.
Otherwise, create the part dwg, add the plating spec on the dwg. Some military programs require a similar note to the "dimensions and tolerances apply after plating or painting unless otherwise specified" note. It varies.
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)
RE: plating tolerance
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group
RE: plating tolerance
Basically, the standard states that it is the processing dims that need identification, not the final dims; and that in either case the final dims have to be provided along with any included process dims.
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group
RE: plating tolerance
2.4.1 Plated or Coated Parts. Where a part is to be plated or coated, the drawing or referenced document shall specify whether the dimensions are before or after plating. Typical examples of notes are the following:
(a) DIMENSIONAL LIMITS APPLY AFTER PLATING.
(b) DIMENSIONAL LIMITS APPLY BEFORE PLATING.
(For processes other than plating, substitute the appropriate term.)
I came across it by chance when looking for something else.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
"Typical examples of notes" meaning not mandatory. We can all do a flip flop as much as we like but every process has its tolerances. If a final dimension with a specified tolerance is needed there is no way to manufacture it without deciding how the tolerances for each process will be specified. We can try to hide it by throwing the burden on the plater but no plater in the world can make a plating with zero tolerance as no machining house can do a zero tolerance dimension. If for example the final outside diameter dimension or a part is 30 mm -0.010 mm and the minimum zinc coating is 0.005 mm, the part must be machined to 30 mm -0.001 to 0.002 to allow the zinc plater to reach the final dimensions unless he will plate, remove and re-plate over and over until he will (hopefully) succeed.
RE: plating tolerance
The form of the note is not mandatory. Having a note, or otherwise indicating when limits apply, apparently is mandatory as indicated by use of the work shall.
As regards the rest of your post, I've previously written that depending on what the specific plating spec says it may be necessary to at least state a minimum required plating thickness.
I've also posted that I think it's probably best left to manufacturing to determine the divide in tolerance between plater & machine shop. It could potentially vary between different platers so I'd probably leave it or ‘pre treatment’ dimensions off the drawings, although as fcsuper pointed out in a previous post ASME Y14.5 does allow for it to be on the drawing if required.
However, I didn’t put my previous post to restart the general debate, just to share information I’d found that states unequivocally (assuming you follow Y14.5) that an indication of whether dimensions apply before or after treatment is required.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
Exactly what I said in my second post. In most high end aerospace/defense companies their manufacturing engineers with the sole purpose of doing process drawings. I don't think it's common in other industries.
Heckler
Sr. Mechanical Engineer
SWx 2007 SP 3.0 & Pro/E 2001
XP Pro SP2.0 P4 3.6 GHz, 1GB RAM
NVIDIA Quadro FX 1400
o
_`\(,_
(_)/ (_)
(In reference to David Beckham) "He can't kick with his left foot, he can't tackle, he can't head the ball and he doesn't score many goals. Apart from that, he's all right." -- George Best
RE: plating tolerance
See: http
RE: plating tolerance
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog
RE: plating tolerance
RE: plating tolerance
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog
RE: plating tolerance
Heckler![[americanflag] americanflag](https://www.tipmaster.com/images/americanflag.gif)
Sr. Mechanical Engineer
SWx 2007 SP 4.0 & Pro/E 2001
o
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(_)/ (_)
This post contains no political overtones or undertones for that matter and in no way represents the poster's political agenda.
RE: plating tolerance
RE: plating tolerance
Although now that I see it, I don't supposed specifying that the dimensions apply after all finishing processes is such a bad idea.
V
Mechanical Engineer
"When I am working on a problem, I do not think of beauty, but when I've finished, if the solution is not beautiful, I know it is wrong."
- R. Buckminster Fuller
RE: plating tolerance
To resolve the issue I need to include limits for the thickness of the plating so that our manufacturing folks can control their machining processes accordingly. I don't like this situation but I have little choice at this time.
I think my best option is to consult with a few plating vendors and specify a thickness range based on their recommendations and our corrosion resistance requirements and let the manufacturing guys sink or swim. I was hoping there was some sort of "industry standard" for this but apparently not.
Please note that I am not bashing manufacturing in general, just the chuckle heads I have to deal with.
Thanks for all of the feedback.
JBK
RE: plating tolerance
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog
RE: plating tolerance
V
Mechanical Engineer
"When I am working on a problem, I do not think of beauty, but when I've finished, if the solution is not beautiful, I know it is wrong."
- R. Buckminster Fuller
RE: plating tolerance
ajack, while not normally a complete drawing I have seen it done that way. The design team came up with the drawing for the finished item. Manufacturing then determined any dimensions that needed to be made deliberately undersize etc and either came up with their own partial plan (drawing) or notes on a travelor or similar/equivalent. It was definitely like this where I worked in the UK.
A lot of the time my guess is if the tolerance is say +-.005" while the plating is say less than .001" they don't really do anything except try and stay nearer the middle of the tol zone for the machining.
vc66, I personally hate the sheet 1 & sheet 2 being treated as almost separate drawings. To me the possibility of confusing as to what state a part is at, either sheet 1 or 2 outweighs the advantages. I've seen it cause problems.
What this thread and related threads/conversations etc has made me realize is just how important it is for the designers to know what the finishing spec says. Some do define thickness, others give recomendations but seem to say that the drawing should state the thickness while if I recall correctly some perhaps don't even go that far.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
RE: plating tolerance
I would NOT leave a plating thickness spec off my part drawings. Doing so would leave yourself open to receiving out of spec parts from your plater. What are you going to gauge your parts to pre & post plating if the proper spec is not called out? That may come back to bit you later.
I recall the ANSI Standards book for threads calling out the proper method for calculating the new BEFORE PLATING sizes.
Hope this helps. There is also another thread in this forum dealing with plating callout on drawings.
RE: plating tolerance
The threads (no pun intended) on this subject really have reminded me just how important it is to know what the spec you call up says and what it says about how it should be called up on the drawing. I also realize that it turns out that some of the information in my earlier posts was possibly wrong.
Some specs definitely do say that you should give the thickness, or at least the minimum thickness, on the drawing.
KENAT, probably the least qualified checker you'll ever meet...
RE: plating tolerance
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group