electro polishing ?

[motumbo]

what would i need to do electro polishing for aluminum and stainless steel ?

[mpierich]

Here's a start...

http://www.pfonline.com/articles/030201.html

I know nothing about it, but it seems like it would brighten the surface but not do much for scratches etc.

[fxstcguy98]

Lot's of money, the chemicals are extremely expensive. Electropolish is basically used as a final surface prep for a micron fine finish for use in steril enviroments. You can't just take some ugly scatched up peice and put it in and majically have a mirror finish, you still have to do the initial prep the old fashioned way.

[motumbo]

Well im not taking scratched up parts and trying to magically un scratch them, i have a machine shop and am looking at way to decrease costs, we do mostly production sporting goods such as paintball guns and golf club putters, and i am looking for a way to brighten up finished stainless steels parts. pasivation, bright dip, or electro polish is something im interested in, but i dont find much info on the subject here.

I need to make my question more clear,

how would you guys " brighten up " stainless steel parts.

The machine finish parts could just use a pasivate to protect them, but it seems to dull them slightly
.
but the beed blast parts are dark and need to be brightened.

any ideas ?

thanks for the input so far......

[sswee]

motumbo,
What is the part finish off the machine? Are we talking about a 125 or a 32 finish to start with? Have you thought about blasting with a different media? Something designed to polish more than give a matte finish. Do you have a seperate bench dept.?

[motumbo]

Originally Posted by sswee

motumbo,
What is the part finish off the machine? Are we talking about a 125 or a 32 finish to start with? Have you thought about blasting with a different media? Something designed to polish more than give a matte finish. Do you have a seperate bench dept.?

16 to 32 finish, the media is a fine glass bead, we have different grits of bead, the fine one is the customers choice for finish.

bench dept ?

[sswee]

Bench dept. is the one that, on aviation parts removes machine cutter marks and preps the parts for coating, on parts for the semiconductor industry removes cutter marks or polishes the parts depending on application. They usually handle any of the cosmetic issues after machining.

On bead blasting parts, dropping pressure on the blasting cabinet to approx. 30psi may give you the desired effect after treating. It makes a substantial difference in anodizing. It has the same texture visually but brightens colorwise.

On electro-polishing, on the finishes your working with is probably what your looking for. That step was always out sourced for the parts that needed it. ie. medical parts and tooling. Therefore I cannot be of help on that.

You have come to a hobby forum looking for industrial answers. There are some here that have the experience to help on some of you inquiries, but you need understand the difference in context of application. Have a nice day. SS

[jimcarry]

Originally Posted by motumbo

what would i need to do electro polishing for aluminum and stainless steel ?

Electropolishing Basics


Commercial applications for electropolishing have been in use since the early 1950's. Most formal research on the process occurred at that time, motivated by the growth and sophistication in electroplating technology. Today there are about 500 industrial installations nationwide, and perhaps several dozen electropolishing job shops.
Electropolishing is often referred to as a "reverse plating" process. Electrochemical in nature, electropolishing uses a combination of rectified current and a blended chemical electrolyte bath to remove flaws from the surface of a metal part.

The typical electropolishing installation is deceptively similar to a plating line. A power source converts AC current to DC at low voltages. A tank typically fabricated from steel and rubber-lined is used to hold the chemical bath. A series of lead, copper or stainless steel cathode plates are lowered into the bath and installed to the negative (-) side of the power source. A part or group of parts are fixtured to a rack made of titanium, copper or bronze. That rack in turn is fixtured to the positive (+) side of the power source.
the metal part is charged positive (anodic) and immersed into the chemical bath. When current is applied, the electrolyte acts as a conductor to allow metal ions to be removed from the part. While the ions are drawn towards the cathode, the electrolyte maintains the dissolved metals in solution. Gassing in the form of oxygen occurs at the metal surface, furthering the cleaning process.
Once the process is completed, the part is run through a series of cleaning and drying steps to remove clinging electrolyte. The resultant surface is clean and bright. In fact, the bright surface is the most identifiable trait...the one that helped coin the name: Electropolishing.
While the process is best known for the bright polish left on a surface, there are some important, often overlooked benefits of this metal removal method. These benefits include deburring, size control, microfinish improvement and others. These metal improvement benefits offer great promise to design and production engineers for cost savings and product improvement.
Although the process is roughly 45 years old, substantial refinements have taken place. Many electrolytes have been developed to allow for electropolishing of a broad range of metals. These newer electrolytes, together with advanced parts handling techniques have combined to improve production yields on a wide range of metal products. and this is just the basics