Vacuum application

[boardmaker 0]

Was wondering if anyone here has used vacuum cups in automation. I work at a sawmill and we have an application that a vacuum cup would work wonderfully on to pull a board about 5 inches or so. The automation side is definitely doable. My question is the combination of a vacuum cup and sawdust. I'm not the smartest guy in the world but I think I can figure out what is going to happen. Do the cups have any type of particulate filter. I've been surfing and found anver corp. and they seem like a good company. I threw them an email to see what they think. You guys got any idea's or suggestions. Lucas

[Bob O 8]

I want to say I have seen some of them with a screen in the bottom of the cup that could act as a filter and you could also pulse some air back through the cup after the cycle to blow off any dust that has accumulated. Hope this helps, Bob

[robh 12]

We use these filters between the suction cup and our vacuum generators. Seem to work pretty, most of the dust that plugs our genarators will go through our cups.

[boardmaker 0]

Since I've never used any type of vacuum application, I'm assuming you do not have to really wait for the suction. The process of reaching out and grabbing the board and pulling it back will probably be done in less than a second. I hope that is possible. Also, this is rough cut lumber (not planed) so it is a little pourous. I've noticed they make cups for just for something like that. Does anyone believe I will have an issue with that? Also, can anyone name any good manufacturers.

[Beuwolf_1 0]

I've done a lot of vacuum applications within the wood working industry. We made machines to lift sheets of plywood into forming machines prior to becoming kitchen countertops. There is no problem with suction at all, but as others have said, filter it before it enters your vacuum generator. The other thing you really need to remember is have enough dwell time for your vacuum to generate prior to the lift, and also ramp the speed slowly. The best way is to have a series of cups, one to lift one end of the board first, and that breaks the "suction" between the boards themselves, and the rest to actually do the lift and carry to position. We averaged one sheet of ply about every 30 seconds, and while that seems slow, that was on a rotating selection system that allowed different sizes and thicknesses, and we seldom had a sheet fall.

[robh 12]

We use Piab. They seem to work well for us. I think Festo also makes vacuum components. Edited 23 May 2006 by robh

[boardmaker 0]

beu wolf, You mention to make sure to have enough dwell time. Here's my situation. A cant passes through a saw to make a board. After passing through the saw, two banks of chains pop up. One sends the cant to a set of chains to bring it back around to be sawn again. The board has two choice, to either follow the cant(this option is not used often) or to be sent futher down the line. What happens is if the board does not have a square edge it sometimes hits both chains that pop up. Since those chains are spinning in opposite directions it causes the board to spin 90 degrees until someone manually removes it. My idea is to have a set of vacuum cups to pop up and literally pull the board onto the chains a couple inches and then drop the board. At which time the cups would tuck back down. This could also happen above the chains we have room. My question is I probably only have 2 seconds to grab the board and move it. Is that enough time? I was thinking about 6 or 8 cups. That was the best I could describe it. I hope it's clear enough. Any and all suggestions are appreciated. By the way, a 16 ft. board is the longest board, 16 inches wide. At very most, they will weigh 50 lbs. max. I don't really know for sure but I would say an average board weighs around 15 to 20 lbs.

[Beuwolf_1 0]

The dwell time I was thinking about would have been about a half second is all. That doesn't seem like much but it is enough time for the cup to conform to the surface of the board and get its grip. Some people make the assumption that a cup is suckin the milisecond it makes contact with the target and don't give it a chance to develop a solid grip. Two seconds is way plenty of time to do your operation. I would think that a bellows style cup would probably be a good choice as well for this application just cause it can conform to a lot more profiles then a solid non-bellows style cup. Hope this helps. Beuwolf

[boardmaker 0]

The cups I have seen on the internet don't look as strong as they sound. What if by chance I would get a product that was to heavy for the cups? When the machine pulled back is there a chance with the cup trying to pull the heavy product and it broke away is there enough suction to actually tear the cup or something of that nature?

[Beuwolf_1 0]

The cups we have used are about four inches in diameter, and last a long time, the biggest issue with wear is when the board is still moving when the cups try to engage. I would suggest looking at some of the standard type industrial cups. There are a lot out there and a wide variety to choose from. I would go with the type that has the steel backing tho, since those do last a little bit longer.

[GerryM 2]

You need to calculate the force on each cup first, then ask the manufacturer. We have a 'purchased' vacuum based hoist that lifts about 50 lbs. So it is possible.