Web Goblin cnc has begun

[Web Goblin]

Jonathan,
the setup page on USBCNC for acceleration shows Acc.[AU/S^2]. In this box I have left it set to 50 which is the default setting. I cant remember what this setting means. I think I did ask Gary at Zapp about this a while ago and I have been looking through some old emails trying to find the answer but cant find it so I dont really know what Ive got it set to. I think I will have to email Gary again about it.

Ian

[Jonathan]

Jonathan,
the setup page on USBCNC for acceleration shows Acc.[AU/S^2]. In this box I have left it set to 50 which is the default setting. I cant remember what this setting means.

It sets how fast the speed of the motor can change, which is important since when the machine changes direction one or more axis must accelerate and decelerate, so if the acceleration value is too low the feedrate will reduce significantly every time it changes direction which includes just moving in arcs and circles. In addition to increasing the time taken to cut it causes the chipload to vary on the cutter which, depending on the size of the cutter, could damage or at least increase the rate of wear.

See 3.4.3.2:
http://www.planet-cnc.com/files/CNCUSBController.pdf

Assuming you're using millimetres, the value is probably in mm/s^2 in which case 50mm/s^2 is far too low. You want more like 500-1000mm/s^2, but not too high as it can cause the machine to shake excessively. Keep increasing it until the motor stalls, then back off a bit to be safe.
As 50mm/s^2 is such a small number you will notice a big difference in the time it takes to cut most things, but particularly parts with small moves, such as engraving.

[HankMcSpank]

Jonathan,
the setup page on USBCNC for acceleration shows Acc.[AU/S^2]. In this box I have left it set to 50 which is the default setting. I cant remember what this setting means. I think I did ask Gary at Zapp about this a while ago and I have been looking through some old emails trying to find the answer but cant find it so I dont really know what Ive got it set to.

Hii Ian,

I've just taken delivery of a USB-CNC 9 axis board....not sure if you know, but there's now a proper support forum (it's only opened recently)....

http://forum.planet-cnc.com/index.php

the software author (Andrej) is very responsive to posts on there.