View Full Version : Slow going around outside corners
erniek
10-02-2009, 04:57 PM
'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.
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 (http://www.diamondlakewoodworks.com)
Gary Campbell
10-02-2009, 08:44 PM
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
10-03-2009, 02:03 PM
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
10-05-2009, 10:12 AM
I am going to try a faster computer, see if that makes a difference.
erniek
10-07-2009, 04:20 PM
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
10-07-2009, 05:11 PM
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
10-07-2009, 08:01 PM
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
10-09-2009, 12:00 PM
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
10-09-2009, 12:14 PM
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.
erniek
10-09-2009, 05:08 PM
Well then I will have to increase my jog speed slightly.
curtiss
10-10-2009, 08:18 AM
6 IPS ? ... thats moving right along
Faster, faster... till the thrill of speed, overcomes the fear of breaking a bit...
kubotaman
10-10-2009, 12:38 PM
Im not trying to change the subject. When you speak of FPS is that speed times 60 seconds the amount of forward movement in a minute?? I think so, but where does a person get the FPS reading in a file? I set mine say at 1, then that is the same as FPS?
Gary Campbell
10-10-2009, 01:20 PM
Daryl...
The 2 speed units most used in CNC machining are IPS and IPM. I am not sure on the usage of FPS.
IPS (inches per second) = IPM (inches per minute) /60
IPM = IPS*60
FPS (feet per second?) could = IPS/12?
The ShopBot control software uses and diplays IPS. It can operate with IPM when using Gcode from the SB Link, but will always display in IPS on the console. All of these can be converted back and forth, but none are the "same"
Gary
Hi Daryl,
Cutting speed is expressed in Inches Per Second (IPS) or Inches Per Minute (IPM). Just multiply IPS by 60 and you get IPM. SB Link uses IPM whereas Partworks uses IPS. Travel is in any direction. X, Y or Z. It is all expressed the same way. Z can also be called plunge rate, but is still measured in IPS or IPM. X and Y can be set different then Z but, someone correct me if I'm wrong in saying, you can't set X and Y at different speeds (not sure why you'd want to).
In SB Link a fairly common cutting speed for 3/4" plywood might be between 4 or 6 IPS or 240 to 360 IPM, depending on your machine (some people push their machines harder). Personally I cut at about 5 IPS (300 IPM).
In a Partworks file you might see a command like MS, 4.0, 1.0. The MS is Move Speed. The 4.0 is your X,Y speed. The 1.0 is the Z plunge rate. You can change these when setting up your tool database in PW's or if you feel ambitious you can modify the file after it is created.
Jog speed is the speed that your machine moves from point A to point B while NOT cutting. When cutting large sheets it is handy to be able to have the machine move from one point to another faster then it will when cutting material. This jog speed helps to reduce overall sheet processing time.
I'm right across the state from you about 40 miles north of Spokane.
Don
www.diamondlakewoodworks.com (http://www.diamondlakewoodworks.com)
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