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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Blisters on ABS Electroplated part after shipment
Q. Hi,
We are facing a problem of blisters on the Front Grill part molded by ABS and Electroplating ( Cu/Ni/Cr )by our local plater. The problem was observed after shipment of parts to various countries and mainly on cold countries.
There is no such defects observed with the parts sending locally in India. The rejection % is about 12% due to said reason. The other ABS parts ( small plated parts ) and painted parts are found ok despatched with same consignment to various countries. The problem found with 12 % plated parts and that is blisters.
Pl advise us is there any special care to be taken during shipment or any agent / additive is required kept along with consignment along with shipment to avoid blisters. IN addition to this what could be the possible reason for such kind of defect. Is it related to Electroplating IF yes what care should be taken. ? IS it related to Molding - Pl suggest what care should be taken. Is it related to ABS raw material ? What could be the possible reason.
- Vadodara, Gujarat, India
2006
A. Blistering is caused by delamination of the metal coating from the substrate and is usually due to poor processing. The reason for the apparent delay in seeing it is due to many possible factors, such as stress in the deposit, solution entrapment or thermal expansion. I have seen it where the ABS moulding was has been done under the wrong conditions and the subsequent plating pretreatment has been ineffective. I have also seen it where Cr(VI) has remained in the moulding and caused poor adhesion. Poor adhesion can be due to any of the following: a) poor moulding caused by wrong processing conditions; b) wrong grade of ABS; c) poor or ineffectual metallising pretreatments; d) poor and/or incorrect plating processing; e) excessive tensile stress in the metal deposits; f) poor process rinsing; g) excessive thermal cycling (only in extreme conditions). This probably doesn't answer your question, but it gives you some starting points to look for the true reason for your failures.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2006
A. Dear Jaimin;
are your partner using high sulphamate and microporous nickel plating on ABS parts before the chrome plating? I think this is the problem.
- PGS ,TURKEY
2006
Q. Thanks MR Trevor and Mr Murat,
I will check the relevant things at Plater's end and Molding shop. But can some one give me an idea about the relation ship between shipment and Blisters- What care to be taken in shipment.
Should we cover the parts with Plastics films or any coatings are available to prevent the part in shipment. Is Sea Sault/ enviornment is creating such kind of defect. What test is recommended for this
Pl advise me
- Vadodara, India
2006
A. Dear Jaimin,
The problem of blisters arises due to poor pre-line parameters which creates poor adhesion, and secondarily if the component is not plated with semi-bright nickel. Semi-bright nickel gives corrosion strength to the weather, as you said it, with cold countries .
- Mumbai, Maharashtra, India
August 25, 2012
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