Question on chinese bed size

[Keith Winter]

I have a question for those of you that have 900x600 working area machines = 23.6" x 35.4" working area.

I'm cutting 23.5" x 33" objects out of 24" x 35" sheets.

1) Can I fit and effectively cut that on a 900x600 machine or would it run into the edges when I moved the bed up and down?
2) Would I be able to cut that full 23.6" x 35.4" area or is that not all "cutting" area?

[Matt McCoy]

I have a question for those of you that have 900x600 working area machines = 23.6" x 35.4" working area.

I'm cutting 23.5" x 33" objects out of 24" x 35" sheets.

1) Can I fit and effectively cut that on a 900x600 machine or would it run into the edges when I moved the bed up and down?
2) Would I be able to cut that full 23.6" x 35.4" area or is that not all "cutting" area?

Cutting -- probably. Raster engraving -- probably not, since you need to account for room for the head to ramp up/down as it changes direction. This is about an inch (0.5" on each side) on the machines I've used.

Hope that makes sense.

[Dave Sheldrake]

You can tweak the standoff from the home position Keith or you will lose 10mm in the X and 10mm in the Y axis (it homes then moves in 10mm) there is also a setting in the syscfg file that controls the bed size the laser understands that can be played with to gain a MM here and there

[David Somers]

Keith,

Just a thought. The cost difference between a 900x600 and the next size up, 1200x900, is usually pretty minimal. I think when I was looking it was only about $150 more? Might just be worth doing regardless unless space was an issue, as it was for me. Also, as seems to be the case around our area, a 1200x900 machine may have a better resale value, all else being the same.

Dave

[Jerome Stanek]

not sure about your laser but on mine that is 300 x 500 I can get it to cut 325 x 525 without hitting anything

[Scott Marquez]

You might be able to cut edge to edge, the biggest problem I foresee is if you have an aluminum frame around your honeycomb bed. I use my machine for cutting fabric and that is one of the things that I have ran into.
Scott

[Jerome Stanek]

You might be able to cut edge to edge, the biggest problem I foresee is if you have an aluminum frame around your honeycomb bed. I use my machine for cutting fabric and that is one of the things that I have ran into.
Scott

I use a piece of egg crate on top of my honeycomb

[Keith Winter]

Thanks for all the replies guys, lots of good info! So to answer the questions.

Dave I understand what you mean, thanks for that! To clarify I can get the whole 23.6" of cut area if I tweak the settings?

Matt & other, I don't 100% understand what you are saying. If I'm cutting 23.5" x 33" objects on a 23.6" x 35.4" working area. I understand what you're saying to mean there is a 0.5" lip on the bed so the material shouldn't interfere with the up and down correct? Do you think I will be able to cut the full area I need to?

David, I have a 1300x900 beast laser. Works fine for this, problem is it eats up massive amount of shop space, this thing is about the size of an old VW beatle! The going to a smaller size is more of a space thing and not so much to do with cost. I haven't been able to find much between 1200x900 and 900x600 work area so I thought I'd gather opinions on if the 900x600 would work.

Scott, are you saying the frame is included in the 23.6" x 35.4" working area or are you saying if I go beyond the 23.5" even a tiny bit it will mark the frame. When you laser beam hit the frame what did it do?

Jerome, what do you mean egg crate on the top of your honeycomb? Doesn't it cut into the egg crate when you cut through things, any fire hazard?

[Matt McCoy]

Keith: On the DC tube machines I have used, the laser head needs about 1" of additional space (0.5" on each side) on the X axis to account for its change in direction (as it moves back and forth). So for a 30" piece, you would need a 31" table and move the laser 1/2" inward to avoid crashing into the machine or limit switches. Does that help?

[David Somers]

Keith,

Even my 900 x 600 can house a small family, provided 2 of the 5 kids are away at college most of the time and they are into cats rather than mastifs for pets. It was a more reasonable size in my shop than the 1200x900 though.

I am afraid I have not pushed its table size limits yet however so I can't tell you what the real limit is.

Dave

[Kev Williams]

I remember my shipping documents well. My 1300x900 Triumph needed a 4 cubic meter (yard) crate...

... a 4 cubic yard dumpster:



Yes, it's that big!

[Keith Winter]

Keith: On the DC tube machines I have used, the laser head needs about 1" of additional space (0.5" on each side) on the X axis to account for its change in direction (as it moves back and forth). So for a 30" piece, you would need a 31" table and move the laser 1/2" inward to avoid crashing into the machine or limit switches. Does that help?

Haha David!

Matt: Ahhh so you're saying I may only be able to cut 1" less (1/2" each side) on that then they list... Well that stinks on ice.

Would someone who has a 900x600 mind spending a couple minutes for science moving your head up and down the bed to verify that it's really 1" less than listed and only a 22.6 x 34.4" cut area? Much thanks in advance!

[Rich Harman]

Keith: On the DC tube machines I have used, the laser head needs about 1" of additional space (0.5" on each side) on the X axis to account for its change in direction (as it moves back and forth). So for a 30" piece, you would need a 31" table and move the laser 1/2" inward to avoid crashing into the machine or limit switches. Does that help?

Not unique to DC tubed machines.

My 1,400 x 900 machine came with a honeycomb table that measured exactly 1,400 x 900, not counting the aluminum frame. Because the frame is a U channel the honeycomb is about 1/16" higher at the edges than rest of it. If you place a piece of material up against the edge you can be sure of some height variation. My correction for this was to construct a frame about 4" high for the honeycomb to rest on with a small cutout for the U channel to fit into. This also greatly reduced flashback.

The interior dimensions of the machine is such that the honeycomb table can be moved several inches in any direction. However, because of the way the laser head is mounted, there is about 50mm of space in the front of the machine that aren't really useable. Yes, the laser can reach that area, but it is past the honeycomb frame at that point. Hence the "1440 x 850" in my sig line. I was also able to increase the X axis length in software settings due to the extra room.

It may well be that the machine you are considering is similar. If I were to order again I would have them include an oversized honeycomb table - one made to to fit the interior space of the laser, with a few mm to spare for easy removal.

[Rich Harman]

Ahhh so you're saying I may only be able to cut 1" less (1/2" each side) on that then they list... Well that stinks on ice.

No, it means that you can raster about 1/2" less than what they list. You can cut right to the edge.

[Ron Gosnell]

Haha David!

Matt: Ahhh so you're saying I may only be able to cut 1" less (1/2" each side) on that then they list... Well that stinks on ice.

Would someone who has a 900x600 mind spending a couple minutes for science moving your head up and down the bed to verify that it's really 1" less than listed and only a 22.6 x 34.4" cut area? Much thanks in advance!

Hi Keith,

My Mars 90 900x600 ..x axis stop to stop 35.5 inches y axis 23 5/8 inches. It's all inside the table cut out and it looks like someone with knowledge could gain a little readjusting the limit switches and reprogramming
the controller. But like Matt said you still need .5 inch each side for buffer. I personally don't think you could do this on mine without a real risk factor.

Gozzie