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Author Topic: Screwcutting issue under Mach4  (Read 312 times)

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Screwcutting issue under Mach4
« on: March 26, 2020, 02:56:27 AM »
Gday all. I have an issue with mach4 when screwcutting, both G76 and G32 are effected.
The spindle speed constantly varies as each cut progresses. Starts out slow around 75 rpm, rises to 400 rpm at the end of each cut. the command speed being 400 rpm. The Z feed is increasing to compensate, but cuts an interesting Thread. The effect is very like CSS as the Diameter increases, except its the Z axis.

Only happens in screwcutting and the correct G97 is specified.

I am using an ESS, but I cannot find any issues in the Configuration.

Hoping someone can help. I took a video of this that I could include if it helps.

Offline Graham Waterworth

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Re: Screwcutting issue under Mach4
« Reply #1 on: March 26, 2020, 08:33:30 PM »
Is your spindle override set above 100%
Without engineers the world stops
Re: Screwcutting issue under Mach4
« Reply #2 on: March 26, 2020, 11:33:07 PM »
Thank you for the response. All overrides are set to 100%.
Since the first post, I have setup a new (Very Standard Mach4 Lathe profile) with no effect.
Tried everything I can think of. Checked the config of both the ESS and Control.

Screwcutting works fine under Mach3 on this computer with the ESS, so something of a mystery to me.

Offline Graham Waterworth

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Re: Screwcutting issue under Mach4
« Reply #3 on: March 27, 2020, 12:06:10 PM »
Have you got Feed Per Rev set (G95)
Without engineers the world stops
Re: Screwcutting issue under Mach4
« Reply #4 on: March 27, 2020, 08:05:32 PM »
Feed per rev is G99 under Mach4 and is set.

This is a link to a YouTube video of the issue https://youtu.be/YqWxuqiohYk

The Gcode is correct to the manual, and also the built in screwcutting wizard as listed below.

N0 (Machine type - MachMotion Lathe Canned Cycles)
N5 (Filename: C:\Mach4Hobby\GcodeFiles\fffg.tap)
N10 (Generated on 03/27/20 at 13:38:32)
N15 G00 G40 G54 G64 G80 G90.1 G99 G18 G21 (Safe Start Block)
N20 %


N25 %
N30 (Starting Gcode for Threading Cycle: ThreadingCycle-0)
N40 G00 G40 G54 G64 G80 G90.1 G99 G18 G21 (Safe Start Block)
N45 %


N50 %
N55 T0101 (Tool Change)
N60 G99 (Feed per Revolution)
N65 G97 S400 (Constant Speed)
N70 M03 (Spindle Forward)
N75 M09
N80 G00 X14.00 Z5.00  (Rapid move to Clearance Height)
N85 G76 P020560 Q0.05 R0.3 K1
N90 G76 X9.72 Z-20.0 R0.0 P1.14 Q0.3 F1.5
N95 G80
N100 (End Gcode for Threading Cycle: ThreadingCycle-0)

N105 %
N110 M09
N115 M05
N120 M30
N125 %
N130 (End Gcode file)
N135 %

Offline Graham Waterworth

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Re: Screwcutting issue under Mach4
« Reply #5 on: March 27, 2020, 09:43:54 PM »
Its as if you have X & Z the wrong way round and G96 commanded.
Without engineers the world stops
Re: Screwcutting issue under Mach4
« Reply #6 on: March 27, 2020, 09:45:43 PM »
Hello,
Could you tell me what type of spindle you have? For example is it step and direction?
Even better can you share your profile? Under help you can package your profile.
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: Screwcutting issue under Mach4
« Reply #7 on: March 28, 2020, 12:20:42 AM »
Will add attachments 1 by 1 in a minute as I get errors (.log not allowed, Filename already exists ETC)

I have attached the Profile + I've been playing with the diagnostics, ESS1.txt (formally .Log) makes interesting reading.

ESS Build 253 and Mach4 4.2.0.4300 (All the latest I think)

Spindle is Step/Dir control (Via C11 Bob built in 0 - 10 volt output).
this works very well in all circumstances other than screwcutting, and CSS works well.
Spindle doubles as Axis "C" but even before this addition, this problem existed.
Spindle pulse is 1 pulse per rev as per Mach3 (C3 optical sensor board). No other encoder.

Looking at the diagnostic file, it looks a bit like Warp9 might have an issue.
Re: Screwcutting issue under Mach4
« Reply #8 on: March 28, 2020, 12:21:42 AM »
Attachment 1 the Diagnostics
Re: Screwcutting issue under Mach4
« Reply #9 on: March 28, 2020, 12:22:58 AM »
Attachment 2 the Profile (Renamed)