Barrel / Basket / Bulk Anodising

A. Dave, My reply stated that you could do parts in BULK. The original letter stated that his parts were for the cosmetic industry, not cosmetic parts. Will you buy your best girl a compact that has a nice touch mark on the cover versus one that does not have any?

I have never met a customer that would accept contact marks anywhere but where it was covered by another part. The paintball industry will not accept it, the military generally will not accept it, the auto industry generally will not accept it, the archery industry will not accept it, the bicycle industry will not accept it, the electronics industry generally will not accept it, so, who will accept it on other than screws? Especially the COSMETIC industry.

A. This one is clearly loaded with semantics issues.

Some of us may be picturing a plating barrel when Jonathan says 'barrel' -- but perhapshe may not care whether it's called a barrel or a basket or a rose as long as it permits bulk anodizing.

Then we have the term 'bulk', which to most people certainly induces visions of large containers of randomly oriented small parts which will make contact with each other, and consequently leave touch marks, at numerous points.

Then we have the question of 'cosmetic industry', which Mr. Holgate defines as a field where "quality surface finish is paramount".

My own feeling is that the chance of this project being a success is slim when he says quality surface finish is paramount though.

A. Basket anodizing is going to have one or more contact marks with zero anodizing and thus zero dye. I do not think that this meets a normal definition of high quality. There are many kinds of tips for anodizing racks. Some are amenable to loading machines. while it does not meet the speed requirement, it will produce a high quality part and probably much faster than what you are currently using.

A. A variety of colors, yes. High quality, maybe, depending on the particular parts and the experience level of the anodizer. You'll have more, and more random, contact marks, and you may have some difficulties getting consistency.

A. I agree with Mr. Gorsich that it's a question of what you are looking for and that a few contact marks don't obligate us to call a finish low quality. After all, virtually every plated or anodized part has at least one contact mark. If it was a watch case, contact marks would probably condemn it as low quality; but I have seen products such as hose barbs bulk anodized and they were fine for their purpose.

Thank you! for your responses. I appreciate all of the input on this topic. I am looking for a jewelry like finish, with consistent color and no visible racking marks on the exposed surfaces. By your answers I surmised that basket anodizing would not work for this situation. Thanks again!

A. You have not given us enough information to give a good answer. Anodize will cost more than phosphate! Your part is small so is going to be a little bit tough to rack. You might do basket anodizing, but you will have several contact points of various sizes on each part with no coating. Several anodizing choices. type 2 which is regular sulfuric anodizing, type 3 which is hard anodizing or what we refer to as type 2 1/2 which is a poor man's hard coat that is done with an additive and a higher temperature.
This quantity is not to be taken lightly for in-house work. You will need a significant dedicated facility. Can you run 24/7 or 24/5. If so, it can be downsized appropriately. Always leave room for increased production at a later time without a major rework of the facility. since you are going to generate chemical fumes and a lot of moisture, even with a good exhaust system, it should be physically separated from the machining operation. Very doable, but not something that you jump right into without hiring a consultant or a very broadly based anodizing foreman and listen to him/her. A lot of engineering items to look at.

A. Perhaps you can tell me what machines I need to make the parts; I'm sure, just like you envision anodizing as simply "dipping", making the parts is nothing more than cutting up sheets of aluminum with tin snips and then bending them up with pliers (or something like that). Except that federal, state and local regulations on air emissions, discharging rinse water, hazardous chemicals such as concentrated sulfuric acid, and resulting hazardous wastes make the proposition of your anodizing much more inconceivable than my making machined aluminum parts! All kidding aside, you stick to "whittling" parts and I'll stick to "dipping" them. There are a number of good anodizing job shops in the mid-west which can be found at this website or other finishing based sites.

A. Bulk anodizing is perfect for that type of scenario, but I can't tell from your description whether your part is perfect for bulk anodizing or not. Because the location of contact marks can't be controlled during the bulk process, the best results are obtained with parts that predominantly curved surfaces (for example, rivets and screws - a combination of which my company does between 2000 and 4000 pounds per day).

adv.
I'm going to try to give you a call to offer a quote, but if for some reason you don't hear from me, please contact me through the link below.

Thanks.

"I'm not expecting a perfect finish on these parts but I would like the whole part to take some color."

A. It depends. If they are flat parts, say washers, which will lay together, the answer is, probably, no. On the other hand, if they are formed enough that they make only point contact, the answer may be yes.

You'll have to try it and see.

A. Hi Shalem. Bulk/basket anodizing is surely the cheapest method, but there would not be other methods if one way was "best". It always "depends" (on factors you haven't told us yet)  :-)

How many parts do you have to do, what alloy are they, do you need dyed or non-dyed, how thick must the anodizing be and why, what reject ratio is acceptable? Please send a photo or drawing of the part to mooney@finishing.com for posting here, then hopefully the readers can suggest whether bulk/basket anodizing is worth pursuing or the parts must be racked. Thanks!

Regards,