Pin Table

[Paul Brinkmeyer]

Ok, pin tables are expensive, so I am going to build my own pin table, but thought I would throw out what I was doing to see if anyone can tell if there would be a problem with what I am planning. Or a better way. I am going to make a base out of .5” Corian, but many materials would work. 12 X 24 because it works for me. I will use the laser to mark out a grid of dots 1” apart. And mark dimensions on some of the rows for easy use. Then I will drill holes in a drill press so I get consistency. I do not need to drill all the way though for my plan, but things might change in the future. For the edges I will attach a strip of corian about 2” wide that sits over the edge 1” and above the rulers. Then I can put holes in this for pins that are taller to use as edge stops.
So far so good. But instead of pins for the bed I plan on using marbles or steel balls. I do not know which is better.

With the grid turned on and the spacing set to 1” I can easily see on the design on the screen where I need to put the balls to stay out of the laser path. Total cost should be really low.
Now the questions are, what am I missing? just seems to be too easy.
And how high does the material really need to be above the bed.

[Michael Hunter]

Drilling all those holes is really REALLY boring!
I know, cos I did over a thousand for my vacuum table with a battery powered drill (used the laser to make a hardboard template).
(Steve/Scott will now pop up and say he can do it in next to no time on his CNC mill).

Will your drill press reach across 6"? Mine will only reach 4.5", so when I do my pin table (I have all the bits, but not the energy) I will make it from 4 smaller bases.

Pins normally seem to be between 1.5 and 2" high (mine are 40mm, but that is just what I could scrounge).

Apart from flashback, I think that you need enough pin height to allow smoke/residue to be sucked out easily from underneath the work.
Corian wont flash back, but you probably want the beam well out of focus when it hits it.

[Craig Matheny]

" But instead of pins for the bed I plan on using marbles or steel balls. I do not know which is better." Personally I think this is a interesting concept I would not use marbles because they are not created equal the steel would be. Now it the balls could be a product that is real easy to clean it would get better like Teflon coated steel balls. The only concern is the exhaust how to keep the balls from being knocked in or sucked in by those that have the massive systems. Please keep us updated on your progress.

[Gary Hair]

real easy to clean it would get better like Teflon coated steel balls

You don't want to use teflon, it emits a toxic gas when lasered. The two things specifically mentioned by my laser manufacturer as "NEVER LASER" are teflon and pvc.

Gary

[Gary Hair]

But instead of pins for the bed I plan on using marbles or steel balls. I do not know which is better.

My vote would be for steel. Marble is laserable and you will end up with the tops of the marbles being different heights after time - not so with steel. I would still go with pins instead of balls, you will still get flashback from the balls but I don't think that's likely from pins. Just my .02

Gary

[Ken Shea]

What is the usual material for the base on these on commercial units.

Pins seem the way to go to me, what would be the benefit of the balls. you know you are going to have to remove the table for a quick jub on something else, then replace the table to begin again.... bump it coming out or bump it going in, and there they go.

[Bruce Clumpner]

I'd build in a registration mark in the top corner for an alternate home (0,0). That way, as long as the table is aligned correctly, you can always get aligned back to your origin. Let us see what you put together.

[Ed Maloney]

Wouldn't the steel balls reflect the laser beam or do I think all steel balls are like pinballs?

[Duane Parcells]

I made my pin table out of baltic birch ply coated with paint saturated with as much silica sand as it would hold. The pins.... I use bamboo skewers with the ends soaked in water for an hour before the cutting. Works great. The table is actually a finger box with a center layer to hold all the "pins" vertical. The longer you make the pins the less beating the box takes. Boxes are 12 by 24. 3 of them makes up the 24 by 36 of my laser.

Duane

[Joe De Medeiros]

I remember reading about someone using pop revits as pins, try doing a search on the form.

[Paul Brinkmeyer]

Good ideas.
Ran a few tests over the weekend using about a ½ inch ball, and Steel balls are out. At least the really shinny SS ones. If the beam hits the ball close to the top, it does mark the bottom of the material. Even as my plan is to arrange the balls so the beam never hits a ball, I know stuff happens. That, and the ball does have a rather large target area on top, making missing the ball even harder. I think any ball is out at this time.
So now I will look for a pin. I like the idea of pop rivets, but the pop rivets I have found vary in height too much.
I will be looking for a common pin that local hardware stores carry to keep costs down first, and it has to be easy to put in the plate move, or take out.
BTW, If the ball concept would have worked, my total cost would have been $10.50.
Duane, I’d like to know about the skewers? How do they really hold up after the beam hits them a few times?

[Rodne Gold]

Why do you actually need a pin table?

[Michael Kowalczyk]

Clean up will be a bugger if you have small parts that will fall through. Also sometimes you need to have support under parts so they don't fall partially and end up on an angle and can interfere with the laser path. Sometimes when a part falls it may fall into the lower path of the next part to be cut and get scorched by the laser. You have to clean it regularly otherwise fallen parts may catch fire and scorch your material.

Problem with rivots is unless you have the hole tight enough for a slight pressure fit, when you raster the material may move from the motion.

Acrylic is a fair to good temporary base but if you use it a lot you will have to replace it. Curious to see if after you have done a few days of laser work, if the base will remain flat or will it start to warp.

I am also in the process of building one that solves these problems.

[Paul Brinkmeyer]

Clean-up is one reason I wanted to go shalow dimple. Nothing falls through the table, easy to clean-up.
Do you think 1/2 inch corian will warp?
I guess if it does, the other issue would be how fast?
Corian is replacable.
what are you using for a pin?

[Paul Brinkmeyer]

Why do you actually need a pin table?

I do ornaments, and I get reflection from the table, making cleanup time consuming. I have noticed the cutting BB is cleaner when supported this way too.
Currently I use scraps of material to space the material 1/4 inch off the table and all is well. But I have to making sure I do not hit a spacer.
That is why I want to build a pin table that has pins easy to move and locate, just using the same grid I use in CD already.
I am oopen for other ideas. Taping works, but I really do not want to tape everything if I do not have too.