Slow feed on first side of cut out?

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Mackerethwoodcraft
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Model of CNC Machine: Quintax pacer 2500

Slow feed on first side of cut out?

Post by Mackerethwoodcraft »

Hey, i’m new to cnc and vectric but getting things figured out. I am having a problem cutting out 2 piece mdf shaker doors, I’m doing the outside cut out through the 3/4 in 2 passes with a 1/2” bit and for some reason the feed rate (which is set at 4m/min) goes down to a crawl burning the bit and the material only on the first side?!? When it gets to the first corners it speeds up to normal rate, but any cut out the first side goes super slow. Has anyone had this problem? I must have something set wrong in the program.

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Adrian
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Re: Slow feed on first side of cut out?

Post by Adrian »

Are you ramping into the cut? Some machines will ramp at the feed rate of the Z axis (plunge) rather than the XY feed rate. Could also be the combined movement is too slow.

If possible it's best to attach the actual Cut2D (CRV) file for questions like this so that settings can be checked.

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Leo
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Re: Slow feed on first side of cut out?

Post by Leo »

4M/M seems like a reasonable feedrate. At 18000 RPM that is .004 Inches chipload.

There is so much unknown about your query.

I could not find and specs on your machine. Is it new? Is it old? Motors?
Cantek does not list your machine on their website.

Can you post your Cut2D file? NOT the g-code - please post your actual Cut2D file.
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adze_cnc
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Re: Slow feed on first side of cut out?

Post by adze_cnc »

Leo: I suspect that it might actually be a "Camtech" Pacer 2500.

Mackerethwoodcraft
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Joined: Sat May 21, 2022 1:13 pm
Model of CNC Machine: Quintax pacer 2500

Re: Slow feed on first side of cut out?

Post by Mackerethwoodcraft »

The machine is a Quintax Pacer 2500. its European (and old 2002) Quintax told to AXYZ (Canadian company) in 2006 they still make a pacer model. the machine runs good the spindle is a 5hp Columbo, and i honestly don't even know the xyz motor make, ill take a peek today. right now it has to run on xmc (old program) on windows 2000. but im looking into a new controller to upgrade machine software. My slow feed rate is defiantly something im doing, i saw the machine working in the shop i bought it from before i bought it.
Ill attach the test door program. I was not ramping in. And it crawls for the first side then speeds up, any help would be greatly appreciated!
Attachments
Test door.crv
(50.5 KiB) Downloaded 48 times
Last edited by Mackerethwoodcraft on Mon May 23, 2022 4:47 pm, edited 2 times in total.

Mackerethwoodcraft
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Joined: Sat May 21, 2022 1:13 pm
Model of CNC Machine: Quintax pacer 2500

Re: Slow feed on first side of cut out?

Post by Mackerethwoodcraft »

Sorry "QUINTAX PACER HD2500" !

Mackerethwoodcraft
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Re: Slow feed on first side of cut out?

Post by Mackerethwoodcraft »

I changed it to cutting in 1 pass and it still does the slow cut on the first side.

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adze_cnc
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Re: Slow feed on first side of cut out?

Post by adze_cnc »

I'm not near a program to look at your Cut2D file. When you say "first side" I presume that is first length of some closed shape. Is that "side" curved? If it is curved does is it have a large amount of "nodes" (or even if it is not curved)? Click the shape to highlight it then press N.

Many nodes on a curve can cause the slowdown you are experiencing.

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adze_cnc
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Re: Slow feed on first side of cut out?

Post by adze_cnc »

Adrian wrote:
Mon May 23, 2022 3:47 pm
Some machines will ramp at the feed rate of the Z axis (plunge) rather than the XY feed rate.
I'm going out on a limb and say that ramps for all Vectric programs to all machines are output by the programs as using the bit's plunge rate not regular feed rate. This limits both the Z and XY travel for the ramp to that plunge rate.

Since my machine has a set maximum 75 in/min plunge rate no matter what speed I tell it to go I lie to VCarve and say that the bit has a higher plunge rate than it really does. On a purely vertical Z move it still plunges at 75 in/min (the hardware maximum). On a long ramping move (especially a spiral) the Z travel is still limited to the 75 in/min but the XY portion of the move is not. Thus this makes for much faster and smoother ramps as the XY movement tends to be greater than the Z movement.

Mackerethwoodcraft
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Re: Slow feed on first side of cut out?

Post by Mackerethwoodcraft »

just a square shape, 10'' x 10'' 3/4 thick. cut out in 1 pass cutting on outside of shape with square corners. The z plunges strait down and does the first strait cut 10'' long SUPER slow, burning the bit and material, as soon as it gets to the first corner its speeds up to 4m/m for the remaining 3 cuts of the square (10'' each). but every time it starts to cut, it does the super slow feed on the first side of the square.

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Leo
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Re: Slow feed on first side of cut out?

Post by Leo »

Sounds like you have plenty of horsepower on the spindle. I will assume the axis drives are equally matched.

I see two toolpaths using a .500 inch cutter. In Cut and Out cut. I don't know which is causing a problem.

Some things I notice

1) your cut depth is .75 inches
2) Your Depth of cut is .1 inches (I am guessing a full depth at .75 would work, but conservatively .375 should be a piece of cake on your machine)
3) Your Feed rate is 5 m/mn (OK - looks good)
4) Your Plunge is .254 m/mn (wow - crazy slow. Maybe 2 or 4 m/mn would be better)
5) Spindle Speed is 16,000 RPM (OK looks good)
6) I don't see and ramping moves ( ramping "could" be problematic with a tiny super slow plunge rate)
7) You can set your material size to be just a TAD larger than your workpiece
8) It is confusing to mix Metric and Imperial. ( just use either or - to make it easier.

Keep in mind that my mind is slipping a cog or 2 from time to time. My friends here will help me along.
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Adrian
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Re: Slow feed on first side of cut out?

Post by Adrian »

What post processor are you using? Sounds to me as though the code is generating as a feed rate for the Z and then not changing to the feed rate for the XY until the command for the corner are reached. Possibly could be the controller itself interpreting the speed changes.

As Leo says that plunge rate you have is very, very slow for a machine like that in wood.

Mackerethwoodcraft
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Joined: Sat May 21, 2022 1:13 pm
Model of CNC Machine: Quintax pacer 2500

Re: Slow feed on first side of cut out?

Post by Mackerethwoodcraft »

the post processor im using is "pacer" from the list available. ive tried changing the pass depth from .01 to .375 and changed the z rate to 4m/m. ill post my results!

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adze_cnc
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Re: Slow feed on first side of cut out?

Post by adze_cnc »

Here's where the bad gcode would actually be useful. Attaching it here would need to be done in one of two ways:
  1. renaming the file to have TXT extension (e.g. my-gcode.nc becomes my-gcode.txt)
  2. compressing it to a ZIP file and posting that

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Adrian
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Re: Slow feed on first side of cut out?

Post by Adrian »

adze_cnc wrote:
Mon May 23, 2022 7:22 pm
Here's where the bad gcode would actually be useful. Attaching it here would need to be done in one of two ways:
  1. renaming the file to have TXT extension (e.g. my-gcode.nc becomes my-gcode.txt)
  2. compressing it to a ZIP file and posting that
Here's the code for one of the cuts using that post processor.

Code: Select all

%
:1248
N20G91G28X0Y0Z0
N30G40G17G80G49
N40T1M6
N50G90G54
N60G43Z24.130H1
N70G0X0.000Y0.000S16000M3
N80G0X19.050Y25.400Z24.130
N90G1Z0.000F254.0
N100G1Y279.400F5000.0
N110G2X25.400Y285.750I6.350J0.000
N120G1X279.400
N130G2X285.750Y279.400I0.000J-6.350
N140G1Y25.400
N150G2X279.400Y19.050I-6.350J0.000
N160G1X25.400
N170G2X19.050Y25.400I0.000J6.350
N180G0Z24.130
N190G28G91Z0
N200G49H0
N210G28X0Y0
N220M30

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