Messages

2271

General Mach Discussion / Re: "run from here" problem

« on: April 28, 2014, 01:57:10 PM »

Interesting test

This will run

#1001 =28.1
G#1001 Z-1.000
code
code
code

This will NOT run. It stalls at the G#1001

#1001 =31
G#1001 Z-1.000
code
code
code

2272

VB and the development of wizards / Re: File I/O being called out of order

« on: April 28, 2014, 01:51:17 PM »

NONE that I am aware of.

(;-0) TP

2273

General Mach Discussion / Re: "run from here" problem

« on: April 28, 2014, 01:15:37 PM »

Another test with

#1000 =31
G#1000  Z-1.000
code
code
code

With this I see what Ian described With RFH it cycles thru the FIRST G#1000 and STALLS out. It will not run any further. So that tells ME that the RFH cannot deal with the G#1000 subsituded for G31. Also with a G31 you still have to OFFSET the Z back to Zero.

I have tried it with G92,G52,G10 and the results are the same. As long as there is a VISABLE Z offset in the code the RFH fails leaving the Z axis HIGH in the sky.

(;-) TP

2274

General Mach Discussion / Re: "run from here" problem

« on: April 28, 2014, 11:26:54 AM »

OK some further testing here . Here is a typical TOM routine commonly used

G28.1 Z0.500         (Run the G28 to find the top of material)
G92 Z0.00              (Set the the Z to zero)
G0 Z 0.120             (Move up to account for the switch travel)
G92 Z 0.000            (reset the Z to Zero)


You can take the G28.1 calls out of the program and the problem still exists with the RFH.  The problem seems to be the G92 offseting. You can see it in the diagnostics page by looking at the total G92 offset values. Z gets offset in the RFH by teh value of the G92s and then when it goes to the Zheight it is too high off the table.

Put the G28.1 back in and remove the G92 calls and the problem goes away as there is NO z offsetting taking place because of the G92s. You can see it on the diag page that6 there is Zero G92 offsetting taking place.

Now you need to account for the switch travel and you can do THAT in "HOMING config" Z offsetting apply the switch travel as a NEG number.

NOW when you run the RFH you do NOT see any offsetting and the Torch ends up at the proper height. 

Just a thought, (;-) TP

2275

General Mach Discussion / Re: Odd glitch in movement?

« on: April 27, 2014, 05:00:14 PM »

IF you go with a lower Vel then your acel is not as sensitive to lost steps.

Your sweet spot will be based on YOUR machines ability to Acell under load.

TEST,Tune,Test,Tune

(;-) TP

2276

General Mach Discussion / Re: "run from here" problem

« on: April 27, 2014, 04:52:18 PM »

ARE you SURE (;-) ? Something seems off. IF your Cam adds in the #1000 =31 in the preamble of the program Then #1000 gets set to 31 at program load.

When you press RFH and inside of that button you reset #1000 =1 it resets the #1000 to 1

BUT when the RFH preruns the Gcode modes it will SEE the initial call of #1000 =31 and set it BACK to 31.

YES??  NO??

I WILL give it a try next week when I get BACK to the shop.

Using the G28.1 and adding in an offset internally(home offset)  seems to work as well BUT I will have to try it as well.

(;-)TP

2277

General Mach Discussion / Re: Controlling THC?

« on: April 27, 2014, 04:37:57 PM »

Got 2 posts for the price of one,(;-) TP

2278

General Mach Discussion / Re: Controlling THC?

« on: April 27, 2014, 04:36:38 PM »

Dave somewhere in your brain is STUCK "You have to slow down on small arcs"  WRONG Cutting with a plasma is dependant on consistant cut speeds and heights.  When you slow down you are altering those constants.  

NOW a fact to remember . Mach3 most times cannot maintain constant feedrates on short arcs. It is a Physical problem with the drives accelleration rates not being able to keep up with the required acceleration between 2 or more short points. There is physically not enough room to do it at the Drives ability to do so. SO now mach3 has automatically slowed down compared to the called feedrate. THAT is where antidive kicks in. WHEN it does slow below requested feedrate MACH3 will shut OFF the THC to prevent torch dive. When the System gets back up to speed it will cut the THC back on.

NOW you talk about cutting small circles in thick plate. THE same applies lets say you are cutting 1/2 thick steel plate. I cut it here at 30Ipm @ 60amps AND I cut everything at that feedrate as THAT is what the torch wants for a smooth cut in that material. NOW a smooth cut is a smooth cut reguardless if it is a straight line or an arc. NOW if the machine can match the accel needed for a particular arc then it cuts the same. IF it gets too short for the machine to maintain a consitant rate then the machine rate will be lower as it just cannot physically do it. SO mach3 slows down and that will change the cut parameter and cause the torch to dive. AND that is where the anti dive kicks in and stop it from diving too low. The quality of the cut will be slighty different in those arc because ONE of the parameters has changed, "Speed".

It will ONLY Be a minor change and it is what it is . UNLESS you have a high END plasma that can auto control machine speed AND torch parameters ON THE FLY you will have what you have.

I spent a LONG time automating an older Plasma torch to have auto control over the power and air settings. Controlled it all automatically from mach3. It would compensate everything on the fly. In the end the overall cut quality 95% of the time was NOT a bit better than NOT having it on. It was a waste of time and energy for "WHAT" we are cutting (Fun doing it though).

SO I suggest you set your max Vel to something reasonable and LEAVE IT ALONE. Then tune the Accell for as FAST as it can react without loss of steps. THEN spend the time to develope a parameters table for your cutting based on YOUR MACHINE. Keep lots of notes. Soon you will find the sweetspot for YOUR machine. AND you will laugh at yourself for worrying about so much.

Then you can have fun at what your plasma can do for you as it is only limited by you imagination to create something to cut. AND that world is EXTREMELY large as to what you can get into and have fun at the same time.

Just another thought is with MACH3  using the THC control thru Mach3 it is NOT fast enough to keep up at HIGH speeds anyway so there is NO need to go there (;-)

Just some thoughts, (;-) TP

2279

General Mach Discussion / Re: Odd glitch in movement?

« on: April 27, 2014, 03:58:44 PM »

HIGH speeds are only good for LARGE tables were you have to jog a long distance sometimes. It is a waste on small tables and will bite you one day jogging at high speed on a small table.

Here I limit the table to 200IPM at 30IPS/s accel. That does a great jog on 99.99% of all cutting we do. That would be from 28 guage up to 3/4" Steel and 28ga to 3/8" alum plate AND we cut a lot of each.

YOUR parameters will be dependant on your table design , rigidity, drives and motor and Feed mechanics ( screw,rack/pinion,belt) type.

(;-) TP

2280

General Mach Discussion / Re: Odd glitch in movement?

« on: April 26, 2014, 07:21:00 PM »

What are your axis setup parameters  VEL, ACCEL ?

If you are getting rounding with THIS file your are either cutting TOO fast OR accel setting too slow for the feedrate.

It looks as thought you are cutting at about 240IPM which is way to fast for the most part for the material you are cutting and AT that feedrate your accel should be about 30 ips/s .

Remember the settings you see for the cutting in the manuals are for very rigid servo driven industrial cutting machines. They can run at very fast speeds and cut square inside corners AT that speed with very fast accelleration rates on the drives.

I am guessing that you are NOT using one of those machines (;-) so your setup and cutting parameters should be VERY different .

For that file and material here I would be cutting at about 130IPM  Cut height .080 with a fine cut tip and nozzle, 40 amp power setting AND I get very sharp inside corners HERE. Fine tune the Feedrate to TUNE the cut quality. It may be a touch faster or slower just depends on conditions and material.

Just a thought, (;-) TP

PS, IAN sorry for taking over your post(;-) but I cut that type material every day on a DIY type machine.