×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

mysterious disappearance of material post plating

mysterious disappearance of material post plating

mysterious disappearance of material post plating

(OP)
We manufacture a Compression spring out of 0.026" tolerance +/-0.0003 wire diameter music wire per astm A228. We send the part out for a commercial thk .12 mil min tin plate. Weird thing occurred when we received the parts back and measured the wire diameter cross section-ally the wire diameter was measuring 0.0251" on average. Could the electroplating process have removed some of the base material? We measured the tin plating thickness at around .2 mil average. We are planning to send the spring out to a lab for evaluation. Just looking for any insight

Thank you

RE: mysterious disappearance of material post plating

you would and should review the plater's EXACT process and chemistry. Either surface prep or some funky stuff in the plating solution could be an issue.

Are you measuring before and after using the same instrumentation and process?

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers

RE: mysterious disappearance of material post plating

Was there an acid etch involved?

Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

RE: mysterious disappearance of material post plating

(OP)
IRstuff
We measure the wire diameter cross section before and after plating using a micrometer using the same method.

Tomwalz
A pickling was performed to clean the surface before tinning.


Thank you all

RE: mysterious disappearance of material post plating

Pickling can remove 0.001"

RE: mysterious disappearance of material post plating

(OP)
CoryPad
I was not aware of that. So what effects the remove amount? Would it be time in the bath and acid concentration?


Thank you this really helps

RE: mysterious disappearance of material post plating

Also include acid bath temperature. Also understand that a spring will corrode at higher rate than a similar peice of annealed, normalized or hot rolled steel or the same alloy composition.

RE: mysterious disappearance of material post plating

(OP)
Thank you all for the information I have learned something new today. I do have one more question. Would there be a physical change to the appearance of the material surface on the part if the acid cleaning was not done correctly?

RE: mysterious disappearance of material post plating

Likely pitted

RE: mysterious disappearance of material post plating

The surface will definitely change after acid pickling. Music wire has a VERY smooth, uniform appearance after the die drawing operation. Pickling will cause the surface to be rougher and more irregular, as it removes metal from the surface.

RE: mysterious disappearance of material post plating

(OP)
IRstuff,
Yes we have requested this information from the vendor.

RE: mysterious disappearance of material post plating

(OP)
The vendor uses two cleaning solutions to prepare the surface for plating
First Nuvat 6-8 oz/gal tank temp 160-180F
Second Maxamp 8-10 oz/gal tank temp 160-180F

I don't think the cleaning solutions would dissolve the material. Could there be a issue with the plating rectifier?
Below are the processing parameters
Sodium hydroxide 0.9 – 1.8 oz./gal.
Plating bath temperature 110ºF - 145ºF
Electrical current 2-4V/500 amp
Tin concentration 1-3 oz/gal
Tin Sulfate 2-6 oz/gal
Sulfuric Acid 7.2 – 10%

RE: mysterious disappearance of material post plating

In some cases they will use a short period of 'reverse polarity' to assure good clean surfaces.
When they do this they are removing metal from the surface.
They could have overdone this step by mistake.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: mysterious disappearance of material post plating

(OP)
Thank you all for the input this has been very helpful

RE: mysterious disappearance of material post plating

(OP)
IRstuff,
Yes the wire diameter after post plating failed the 0.026 +/-0.0003 spec. The wire diameter was measuring 0.0251 to 0.0258.

RE: mysterious disappearance of material post plating

(OP)
IRstuff,
We are waiting for lab results ,so we do not have that info yet.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources