[IRVING-WILLIAMSON]

Hi everyone, I'm just about to close the purchasing with AVID, and because I was warned by themselves about the accuracy because the machine will be 7ft wide, I'll REALLYappreciate if some of you share some of your experiences with me about such a wide machine, and specifically how (or if) 7ft wide affect the accuracy.
I'm absoltely new in this CNC world, and I wouldn't like to throw my money, so any experience will be appreciated. Thanks!

[ger21]

What are you using it for?
The biggest issue is that the gantry beam may not be rigid enough, and will sag and flex.

It shouldn't really be any less precise, but may not be rigid enough under cutting conditions.

Note that precision and accuracy are two different things.

[MARV]

You haven't said what your expectations for accuracy and feed rates are. If you are doing laser work and not expecting high rates of movements in XY, the expanded machine size may not be an issue. But the folks at Avid know their machines limitations well, so I would listen to their advise.

[IRVING-WILLIAMSON]

Hi, thank you for your post. I mainly need to cut FRP sandwich panels, made of a 2mm thick fiberglass skin, 25mm thick XPS core, and another 2mm thick fiberglass skin, and as a second option, ACP panels, made of 0,5mm thick aluminum, 3mm polymer core, and another 0,5mm aluminum. Of course I'll need some solid wood and plywood too.
I didn't know the meaning of precison, and after a quick research I'm afraid I'm not understanding properly the difference between precision and accuracy: Could you please explain to me the differences between both indicators?

[MARV]

Given what you are cutting, another question to ask is what quality of cut are you expecting? In metal working, a variance of .001" may be a lot, with woodworking, .005" to .015" may be acceptable. And if what you are doing is for general construction work, quality of cut may not be an issue.

However, it sounds like you may be doing production work? How many panels per hour, per day? That alone might be beyond the capabilities of the device you are specifying for purchase. If your duration of use is for 4 to 6 months to get you to the next level, then replace with a more durable machine, your expectations may be reasonable. Still, I would listen to what Avid is expressing.

[shepditch]

To answer your precision vs. accuracy question - precision is about repeatability and accuracy is about being where you want to be. Think of a target shooter - hitting the bullseye is accurate, but missing all your shots a foot to the left, but in a tight grouping, would be precise.
For your machine, I would think when you learn where your tolerances are, you could factor in any flex/error and account for it. As long as it is *consistently* inaccurate, it will be precise.

[Kosh]

Have you asked yourself how you're going to "work" in the middle of that table? Ie, what if you need to zero the bit at a spot on top the material? It'll be 3 1/2 feet away from the edge, my back still hurts from just tramming my 4x10 table in the middle, over the weekend.