Slow going around outside corners

[erniek]

'veI noticed that when the link is cutting around a square outside corner of a part it actually goes is a very small circle. On my machine it slows down a lot, takes about 2 seconds in each corner. I was wondering if there's a way to speed this up to save time and to prevent the bit from heating up and wearing out faster. I'm using a PRT with a spindle cutting at 6 ips.

[dlcw]

Ernest,

That one I've never seen. I've cut well over 100 sheets of different types of material with the link and never had it do as you are describing. My machine approaches the corner, slows down a little to make the turn, goes around the corner and takes off cutting again. I'm running a PRS Alpha with spindle. What version of SB Control software are you running. I'm running 3.6.1 (to chicken to move up).

Have you posted to the Thermwood forum or Thermwood Tech Support on this?

Don
www.diamondlakewoodworks.com

[Gary Campbell]

Ernie...
Try adjusting the slow corner speed parameters according to Brady's Ramping article : http://www.shopbottools.com/BradysTricks.htm#Ramping

It works!
Gary

[erniek]

I'm running version 3.6.4 or 3.6.5 not sure which, it's second latest version as of yesterday. I did increase the slow coner speed to 85. Didn't notice a difference.

[erniek]

I am going to try a faster computer, see if that makes a difference.

[erniek]

Faster computer made quite a difference. It's a lot faster going around the outside corners like that. I was able to increase the jog speed from 8 to 12 inches per second too. How fast can a PRT jog?

[erniek]

Looks like I spoke too soon on the increase in jogging speed, after running it a while it started to stall out at times and lose position. Perhaps the motors don't perform as well when they get hot. I have noticed a increase in speed when 'V' cutting lettering.

[thewoodcrafter]

Do you have an Alpha or a Standard?
I don't think a standard can cut a 6IPS.
I don't think they can jog at 12IPS either.
No wonder you are loosing position.
My PRT Alpha is cutting at 6IPS (1/4" bit)and jogging at 20IPS.

[erniek]

Yes it is a PRT Standard. It can cut at 6 IPS. I cut 5/8" melamine in a single pass at 6 IPS no problems no losing position. Well actually two passes, the first pass clockwise leaving 0.020" and the second pass counterclockwise. I use a 1/4" compression spiral at 13,200 RPM. Jog is set at 8 IPS. When I surface the spoil board I run it at 9.5 IPS (not as critical if it loses position) When the motors are cold it can jog at 14 IPS but won't keep it up when they're hot.

[thewoodcrafter]

Man, you are running at the edge!!

PRS specs show cutting at 5IPS and jog at 8.3IPS is max.
I would not run your machine at those speeds if it were mine.