This may be a stupid question.......

[cnc4me]

I know its a 2x2 but can it actually cut a 24 in square? Which would mean material larger than 2x2. Also I have noticed that some machines used slats that are cut sort of like a saw and others are just straight bars. It would seem too me that the saw shape would last longer as it would not be cut as much as the bar style. Whats your opinion? I thought it could be a good first project to cut the saw shaped slats for the my machine.

Thanks

[SoundManCO]

I asked the same questions before I ordered mine. The tool path is 24.25" so it will cut slightly larger than 24". If you add a plate marker it will eat up some of the tool path, it you mount a hand held torch on your own you could eat into the tool path depending on your mount. You can cut larger than 24" by indexing the material being cut and moving the machine or the material. The support bars should be perpendicular to the majority of your cuts to make them last longer but I know I will have to replace them from time to time.

[Torchmate]

We have tried the saw tooth shape. It just results in more tip-ups. This is where the part falls partially free and then partially tips up to where the torch might hit it. Just something to keep an eye on. I have seen slats with literally 1" of slag on both sides. They last a long time, even flat the way we suggest. When they get too caked with slag, pull them out and flip them over. In a perfect world, nothing falls through. Freed parts just sit flat once they have been cut. One less thing to have to worry about.

[cnc4me]

Thanks for the info. I never thought about the parts tipping into the slats, so for sure I will make them straight. That was to date the best tip I have received. If a part were to tip in and after the head hit the part would the machine stop? Or would it try and drive through it? How easy is it to damage the machine in this way?

[Torchmate]

Originally Posted by cnc4me

Thanks for the info. I never thought about the parts tipping into the slats, so for sure I will make them straight. That was to date the best tip I have received. If a part were to tip in and after the head hit the part would the machine stop? Or would it try and drive through it? How easy is it to damage the machine in this way?

This is one of the reasons that we don't go huge with the motors. The only thing you could damage is the torch itself and you have to be going pretty slow to do that. Slower speeds put more torque to the motors which gives you a better chance of hurting the torch head. Our servo based electronics and machines have safety's built into them to trip before the torch head gets ripped off. Servo's are the opposite of steppers. The faster you go the more torque they put out. They also communicate back to the drive box and tell it when too much resistance is met therefore killing the power.

Arc Voltage Torch Height Control helps with tip-up's as well because the torch raises up 3" between cuts to avoid hitting anything. Better yet is that it does it in about a half a second so it doesn't slow you down too much. So, if you have AVHC and use flat slats on 3" centers, it takes a pretty unique part to tip up more than 3" and catch the torch while it is traversing to the next cut.

[HardcorewannabeXJ]

The stepper motor control system is a open loop system, where the motors can not tell the controller there is an obstruction and it can't move any further. The stepper motors will simply stop their motion and "slip" so the machine won't move any further. The potential for damage is limited due to the fact the torch head is mounted securely in the collar which is hard mounted to the gantry. The only soft parts are the torch head itself and it is well supported and protected. On a table the size of a 2x2 it is much easier to manage and control these events then a 5'x10' machine.

[StinkBug]

Originally Posted by HardcorewannabeXJ

The stepper motor control system is a open loop system, where the motors can not tell the controller there is an obstruction and it can't move any further. The stepper motors will simply stop their motion and "slip" so the machine won't move any further. The potential for damage is limited due to the fact the torch head is mounted securely in the collar which is hard mounted to the gantry. The only soft parts are the torch head itself and it is well supported and protected. On a table the size of a 2x2 it is much easier to manage and control these events then a 5'x10' machine.

To expand on this, I have had things jam the movement on my table a few times. Nothing gets damaged, but the motors do "slip" and cause the computer to think the table has moved, when it has not. This screws up the positioning for the next cuts, so it's not a good idea to just press go and walk away from the table. Worst case scenario it'll start cutting into a part that's just been cut, or just in the wrong area of the sheet. Best case it drops the torch off the metal, never gets the pierce OK signal and stops. Either way, its not the end of the world, but you could end up wasting some material if you're not paying attention.

[waynehartwig]

Originally Posted by StinkBug

To expand on this, I have had things jam the movement on my table a few times. Nothing gets damaged, but the motors do "slip" and cause the computer to think the table has moved, when it has not. This screws up the positioning for the next cuts, so it's not a good idea to just press go and walk away from the table. Worst case scenario it'll start cutting into a part that's just been cut, or just in the wrong area of the sheet. Best case it drops the torch off the metal, never gets the pierce OK signal and stops. Either way, its not the end of the world, but you could end up wasting some material if you're not paying attention.

Ditto...I've noticed the same thing. One of the reasons that I don't walk away from the machine while it's cutting. I just put my 'plasma' glasses on and watch it. I think it's pretty cool to watch anyway But on boring parts, I do find myself wanting to do something else.

[Torchmate]

It definitely pays to have your slats closer together to avoid large tipups. Costs a little more to put them in, but saves you from having to sit there and watch it. Our guys here will spend a little more time nesting small parts so that they have the least chance of tipping once free. That allows them to go do something else when the machine is processing a plate.

[LASER]

More form the laser guy;
To avoid tip ups I always tab my parts in, just enough that they shake out later.

They next evolution and I am guessing it is how the bigger machines work. Would be servos with collision sensing. Even steppers with linear encoders would work for this.