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Anonymous Poster

Process Engineer

01/26/2008 8:27 AM

We are experiencing pitting after chrome plating and suspect the cleaning process is not working. We use a Branson vapor Degreaser with an ultrasonic. Can anyone suggest another method of cleaning off residual oil after machining? We want to clean just prior to chrome plate any help would be appreciated.

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#1

Re: Process Engineer

01/26/2008 9:53 AM

How about electroclean?

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Anonymous Poster
#2
In reply to #1

Re: Process Engineer

01/26/2008 10:25 AM

Thanks will look into it!

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#6
In reply to #1

Re: Process Engineer

01/28/2008 9:51 AM

And Copper Plating prior to Chromeplating?

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#3

Re: Process Engineer

01/26/2008 11:33 PM

Caustic cleaner followed by electrocleaning is what we used industrially.

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#4

Re: Process Engineer

01/27/2008 9:30 AM

"Cheap, Quick and Effective post-machining pre-cleaning"

We used to pre-clean turbine blades immediately after machining with a heated citrus solvent based ( de-limolene I think ) product in a specially designed Landa parts washer that didn't submerge the parts but rather suspended them in a basket and had a spinning spray arm. The parts washer had an oil skimmer to remove the floating oil.We would follow that with a 150 F hot water post "soak rinse" to remove most of the residual cleaner making the final cleaning easier and quicker.

NOTE: The plater would the final clean just prior to chroming.

Also if the parts have been blasted with media, that may be giving you trouble.

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#5

Re: Process Engineer

01/27/2008 10:29 AM

I disagree with the suspicion that the pitting is due to failure to clean.

Failure to clean would result in lack of adhesion/ staining/ and peeling.

Pitting, (Presuming Hard chrome, you didn't say)is often the result of exposed manganese sulfides on the surface of the material (Again, I'm presuming steel, You didn't share substrate with us either). the manganese sulfide is not a conductor, and the chromium will not"bridge" the sulfide, resulting in a pit. if material had heavy scale that had not been removed prior, that could also be a cause. EVen if the material was shot blasted, there could be residual scale at the bottom of the shot produced impingement.

Proper description of the process, and material involved, as well as confirmation of the failure mode: 'pitting' will enable a thoughtful and analytical approach to solving your problem, instead of the rush to confirm your "suspicions."

Team oriented problem solving is not the same as being lead in a cheer.

milo "what is process, what is material, how about photo of the 'pitting'

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Anonymous Poster
#7

Re: Process Engineer

01/29/2008 5:08 PM

May want to consider Impregnating(filling voids with curable polymer resin) your parts before plating:

When used in preparation for plating materials, like acids, or painting prep solvents, that could later bleed out of the pores causing finishes to discolor, blister, pit or peel.

Porosity problems cause castings, powder metal parts, plastics, ceramics and other porous substrates to leak through the body.

Production management is challenged to solve this problem due to increased production demands, soaring scrap costs as well as quality control.

Inherently, powdered metal parts have high percentages of voids. After sintering and loss of the wax binders, impregnation improves the machinability of sintered parts.

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#8

Re: Process Engineer

01/29/2008 7:28 PM

You have not told us the material that you are plating.

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