Some of the most common questions.

Posted by Joe Amick on October 25, 2021

I thought I would share some of the most common questions I get and the related answers. This will not be a deep dive by any means but rather a few of the most common.

The first is more a statement than a question.

I have a single belt sander so I have been de-burring for years.

Well I hate to be the bearer of bad news but that's not de-burring. A single belt will 100% grind the surface but it just pushes the bur over making the edges even sharper. You need at least a second step to remove the bur from the edge and even if just a small bit break the edge.

Should I get a dual sided machine?

In 99% of the cases no. While it might seem a great idea on the surface the added cost and limited aggressiveness tends to make them less effective. If you have to put a part through two or three times what have you gained? Single sided machines will be more aggressive requiring fewer passes but have more handling time. That time is offset by not having to run them three or four times.

I cut with Plasma but its HD Plasma so my bur is minor.

Plasma can be a tough to deal with. The dross and re bonded material can be hardened by the heat of cutting. That tends to be why you can mechanically knock it off. Its hardness makes it brittle and so it will chip off. To remove this via machine requires grinding through whats there to get back to the surface. Then there are the chunks of slag that will come free. You are just not going to pick them up with dust collection and that has to be dealt with in some way.

Are cross belts the best way to do bur removal?

There is not a yes or no answer here. It will depend on what you need to do as there are some cases where they make sense. In a more general sense the cost of the abrasives used in most cross belts makes the answer a no. It will depend on the exact need but don't over look the cost of the cross belt replacement.

If I get a vacuum table in a machine I can do small parts right?

This again is a situation with no clear answer. I am not a fan and I want to say that upfront. To pull numbers out of the sky for conversation, if the vacuum bed has 100 total holes pulling vacuum, and your part only covers 15 of the them the vacuum wont hold on to the part. The air in the vacuum system will just flow to the open holes. You have to cover all or most of the holes to make the system actually pull a vacuum. With small parts that can be an issue. Then there is the cost of the feed belt and the upkeep on the vacuum system that will be ingesting sanding debris.

Dry vs wet whats better?

Short answer is dry would be better. Longer answer would be it depends on what you are working with. If you process titanium for example it should be 100% wet all day every day. The upkeep on wet machines and the inevitable rust can be the thing of nightmares. You can get a wet machine made of stainless steel but it will cost so much most wont do it. Adding 30 to 50% to the cost to get it made from stainless is something 1% of companies will do. Dry machines don't skirt the rules and have their own issues. In a general sense a good dry machine with a properly setup wet collector is better than a wet machine.

Can I get a machine that can grain and debur in one pass?

If you are willing to compromise you can. When you grain you need speed in processing. You want the part to get from the front to the back of the machine as fast as you can. This limits the zig-zag patter of the sanding belt tracking. But for bur removal you want to slow down and give the machine time to work. So you cant do either task perfect when you attempt to do them together. Your speed will be lower than needed for the best grain but still faster than you need for good edge rounding. You will need to compromise or break them in to separate tasks.

The last point will be one that gets asked a hundred ways. Yes you can buy a machine made in Asia that will be cheaper than any number of other machines. The reason you don't is the fact that its a machine means its going to go down at some point. Its just a fact of machines in general from a lawn mower to a high end laser they will go down. Having a 12 hour time difference with the company that built it and them not speaking English are going to make your day even better than it already is. If you need a stop gap for 18 months then by all means buy that cheap machine. But know going in what you are getting and why. Keep your expectations in check and be prepared to figure things out on your own. Every one has to start some where and while the budget wont allow for your dream machine most manufactures offer smaller entry level machines. Look for one you can use as you grow. The small more manual machine is great for small batches or R&D work long term. Its a good jumping off point that allows you to have a good quality machine that will hold up and keep its usefulness long term. If you get a dirt cheap machine from Asia that wont be the case most of the time.

 

As always I am happy to answer your questions about any form of finishing from graining to mirror polishing. Feel free to send me any questions and I am happy to help.

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