Unexplained slow cuts

[jTr]

Using partworks to convert Sketchup vectors for ply cab cutouts.
All goes well when machining, but unable to figure out this behavior:

When doing final cutouts, cut speed drops to what appears to be about 1/8 - 1/4" per second (excruciatingly SLOOOOW....). This will happen on a rectangular side up to 30" length, so I don't think it's a speed ramping issue. Upon completion of that leg and continuing to next side of rectangle, it shifts back to normal speed.:confused:

Qualifiers:

Dados, rabbets and hole drilling processes are perfectly accurate and smoothly executed by machine prior to final cutouts.

Appears to be happening on initial leg of cut only, and even goes full speed upon second pass over same "slow" side of cutout.

Using two climb cuts, one final conventional cut, and will do the same on first side of final conventional through cut, but not same side it slowed on for initial passes. I have copied rectangle to additional layer to generate final clean-up conventional through cut, as I thought it was necessary to enable batch processing of toolpaths.

Thought it may be duplicate vectors, but just cut a single sheet and still had partworks open, so I immediately double checked - no open or duplicate vectors in drawing.

In anticipation of this issue, I completely erased imported rectangle cutout vector and re-drew in partworks to be assured it was not a Sketchup remnant, but experienced same result.


I'm stumped

[gundog]

Make sure the tool you use is not set for inches per minute IPM when you thought it was inches per second IPS in the tool data base.

Mike

[steve_g]

Jeff

Can you isolate and post the code for that part?

SG

[feinddj]

I have had that problem in Aspire as well. Maybe connected to SB. I find that if I go back and rewrite the same line that went slowly in the editor, the problem disappears. Is it consistent with the same line in the file?

Ghost in the MaCNC.

David

[jTr]

Michael - Have verified tool speed. This is same bit cutting one side of a shape and shifting back to full prescribed speed upon turning corner to execute next side (no tool changes or jogs in between).

David - Will take notes and specific line numbers on next batch of cuts. I was not doing so on this run until the last piece, as I was assuming Sketchup related duplicates I may have missed in generating toolpaths were responsible.

Steve, I've isolated the last part I cut that did this. Code shown is start of that cut, which is exactly where things dropped to slow speed, then resumed on 2nd side of vector. I am a newbie, but I think I understand correctly:
5th line down shows MS,4.0 = cut move speed 4ips(?) with second number indicating plunge speed 0.5 = plunge speed 1/2 ips (?). If I am correct, I believe last line below shows the exact command to move through a 23.5" cut, which is 1st side of cutout where the slow speed issue shows up:

'New Path
'Toolpath Name = CUTOUTS1 climb
'Tool Name = 1/4" DOWN (RD2100)
TR, 8500
MS,4.0,0.5
J3,0.000000,0.000000,1.200000
J3,0.316280,0.320760,0.200000
M3,0.316280,0.320760,-0.300000
M3,0.316280,23.820761,-0.300000

Below is the very next line of code that generates 2nd side of rectangular cutout, where machine snaps out of it and moves at correct rate of speed:

M3,32.066269,23.820761,-0.300000

Further qualifiers:
I did a single cab side tester 1st thing in AM as I am a newbie and wanted to verify all OK with an MDF scrap. Different part from code shown, but lost communication halfway through 1st leg of cutout there.... related? No other comm issues for the rest of the day, so chalked that one up to high humidity and MDF dust in my normally arid environment.
Cut 7 sheets on that day, each one displayed at least one instance of this behavior, but no more than two or three per sheet. Average piece count per sheet was 8.


Thanks for the help!
jeff

[jTr]

Update:
Have been experiencing "USB Problem" message on spindle warm-up with increasing frequency lately. Upon taking second run at it, typically clears up and I can run machine without errors.

Been at it for over an hour now, and unable to get past this issue - SB3 refuses to run after "USB PROBLEM" and reboot is necessary.

Also - Message box pop up labled SB3 states: "Due to software update, the toolbar menu bar has changed. Would you like ro restart your computer and load the new toolbar". Not connected to internet - never have been with control computer - how can it be acting like it detects an update???

3rd message of interest - computer indicating it has detected a new device and / or unknow device is experiencing problem.

Machine is 3 months old - maybe 30 hours total run time on it.
Not confident in USB connection based on numerous issues posted by others, so a while ago, I sealed hub connections by firming up w/ electrical tape, enclosed in a plastic food storage container attached to wall to avoid any dirt or jostling issues. Since day one, I've experienced random USB and comm error messages, but nothing fatal til now.

USB Cables and computer as new as machine.

[steve_g]

"Due to software update, the toolbar menu bar has changed. Would you like to restart your computer and load the new toolbar".


I've gotten this message regularly over the years with different computers and OS I always say "no" and continue on my way...never heard of anyone else getting it till now.

SG

[garyc]

Steve, Jeff...

"Due to software update, the toolbar menu bar has changed......".

This message will appear when there has been a change to the Custom files. These files are scanned prior to SB3 loading, and the message is "normal". I have always accepted it in the affirmative.

Look over this post: http://www.talkshopbot.com/forum/showthread.php?p=129807#post129807

[dlcw]

Steve,

I get that message frequently on my setup. I do what you do, say NO and continue on my way. It happens when the software crashes or has a comm error problem and I have no choice but to shut down the control software leaving the spindle spinning round and round where ever the system had a brain fart.

I just figured it was one of those gremlins running around in the software....:eek:

[dttworld]

Update:
Have been experiencing "USB Problem" message on spindle warm-up with increasing frequency lately. Upon taking second run at it, typically clears up and I can run machine without errors.

Been at it for over an hour now, and unable to get past this issue - SB3 refuses to run after "USB PROBLEM" and reboot is necessary.
.......

I just got the USB error for the first time without running the spindle. In my prior job I built research robots for a defense company. One of our bots had problems talking to the sensors over Firewire. After running some experiments and determining the problem was due to return currents in the chassis/ground, I told the boss I could fix the problem for a few hundred bucks. I bought one of the Tripp Lite isolation transformers below and put it in between the computer and 120VAC inverter on the bot. All the software guys thought of it as some magical box that would make electrical problems go away! Gonna buy the same thing for my Shop Bot PC to see if it helps:

http://www.tripplite.com/en/products/product-series.cfm?txtSeriesID=839

[steve_g]

"This message will appear when there has been a change to the Custom files"

What kind of changes? I haven't made any changes I'm aware of...

SG

[jTr]

OK - Here is solution:

Reinstalled SB3.
SB3 complained during setup that it could not find machine, though I was plugged into same port since day one. After much coaxing from the program, I switched to USB port 4 on my laptop, as that seemed to be where SB3 was expecting it.

Ran three sheets last night sans RPM control, otherwise perfect behavior.
Upon booting this AM, things are perfectly fine and RPM control has been realized, simply after an overnight rest.

If a problem arises in future, I will refer to Gary C's contribution on exactly when to plug that cable in during program install for optimal comm performance. This data should be inserted into SB Manual - just imagine all the end user and support confusion it could save!

I thank you all for your support and committment to keeping us all happy botters!!!

jeff