Metal finishing Q&As since 1989
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Brightening Hard Chrome Plated Surfaces
Q. I'm very interested to know more about Hard chrome processes. I knew that the surface of the part will be dull in normal chroming process, certain degree of polishing may be needed. But can I know the way to increase the brightness and surface appearance of the part after hard chroming. And also be able to chrome the sharp corner area, especially in pocket area. Kind assistance and advices very much appreciated.
Angel Wang Jia Jia- Malaysia
2002
A. Hard chrome does not have to be dull. On the contrary, it will plate full bright IF the chemicals are in spec and it is not a heavily contaminated tank. You will find in many publications that there is a box or envelope on a graph of tank temperature vs applied amperage. If you are in this box, it will plate full bright. If you are out of the box it will not and you need to adjust one or both parameters.
Now, to get the tank to plate on inside corners, you will need conforming anodes or auxiliary anodes, properly shaped and placed properly to achieve the desired effect. Not brain surgery, but time consuming to find the ideal setup.
James Watts- Navarre, Florida
2002
Q. Thank you Mr. James.
However, if the sharp corner at the pocket is have complex profile, it is very difficult to achieve an anodes that is having near similar sharp. Moreover, the whole process is not economical. Are there other ways?
Anyway, thank you very much.
Angel Wang Jia Jia [returning]- Malaysia
2002
A. I have never seen a shape that I could not plate, regardless of how complex, but, not cost effective is another story. Consider switching to electroless nickel.
James Watts- Navarre, Florida
2002
Hi Mr. James,
Thank you for the reply. Well, I agreed with you that the profiles may not be extremely complex, but the time consumed is not justified. Anyway, Electroless Nickel is one of the option, but not recommended so far. For example, Hard chroming on the cavity bar of an IC mould used in the semi-conductor industries. Well there are people do such plating, but rather expensive, and we are also facing vendors' problems and quality issues. Maybe, I shall have to find way and method to plate diamond on such cavity bars. Well. Thank you for the advice.
Regards,
Angel Wang Jia Jia [returning]- Malaysia
2002
Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)
High Gloss Hard Chrome Plating of Rotogravure
Q. Ours is a Flexible Packaging Industry.Here we use to print, laminate and pouch for packaging Food and Non-food products.
Printing is done on Rotogravure M/c where the copper cylinders are etched to the customer's design. The etched cylinders should be chrome plated to give a high gloss so as to print with more accuracy.
We want to know about Hard Chrome plating of the cylinders. Usually the cylinders, after Chrome plating has a dull effect. Temp : 55 °C , Electrolyte : Chrome Solution , Anode : Chrome Alloy, Cathode : Copper Cylinder, HENE 1 & 2, Barium Carbonate for reducing Sulphate content. What could be done for a typical chrome plating bath to get high gloss finished cylinders
Santhosh RamaswamyElectroplating - Coimbatore, Tamil Nadu, India
2004
2004
A. Have you tried to plate with bright chrome plating solution. The basic content of this plating solution are
1. 300 g/l Chromic Acid.
2. 3.0 g/l Sulfuric Acid.
3. Hard chrome plating brightener additive.
Regards,
Chua- Selangor, Malaysia
Ed. note: full name please, chua. Thanks.
A. You need the bright finish only on the outer surface of the roll where the blades are in contact (not in the paint microcells). You can do that by polishing while rotating with emery paper grit size 1000 or finer (in some places it is known as 000 three zeros).
Guillermo MarrufoMonterrey, NL, Mexico
2004
Q. Are there additives and/or brighteners for hard chrome plating?
kelem tizazuammunition engineering industry - addis ababa, Ethiopia
August 25, 2015
August 2015
? Hi Kelem. That's a good question! I've never heard of them myself, but Chua says yes, and I see them listed for sale on Alibaba.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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