Table (axis 1) stutter

[Marius Gouws]

Good afternoon
I have a problem with our machine and that is when it accelerate and de-accelerate the table stutter. When we cut something with a small arc it looks like i have cut it with a jigsaw (freehand). Now I have stumble apon something in the manual. If you do a Ctrl + T then I get the following
Tangency Factor = 1.000
Arc Speed Factor = 1.000
Acceleration 1 = 15.000
Acceleration 2 = 15.000
Acceleration 3 = 100.000
Acceleration 4 = 15.000
Acceleration 5 = 15.000
Acceleration 6 = 15.000
Acceleration 7 = 15.000
Acceleration 8 = 15.000
Acceleration 9 = 15.000
Now i want to know if that is correct, because i think that might be the problem, and if it is how do I correct it?
Thank you very much in advance

[Daniel Vonderheide]

Marius,

Usually when we see machine studder that results in a bad cut it is caused by one of two things. The first is mechanical wear in the machine causing lash. The second is the actual program itself. If the geometry you used to create a program was "dirty", then the program will be "dirty" too. The numbers you posted look fine. I would start by looking at the mechanical aspect of the machine. Check to see how much lash you have in each axis. If you have very little to none, then start looking at the programs and how you are creating them. If you cannot find any issues send us one of the programs that you are having issues with and we can advise you on what could be the cause of your issue. Send any files to program@thermwood.com , making sure you add your company name, contact information, machine number, and a brief explination of the problem. Thank you.

[Marius Gouws]

hello Daniel
We all here use eCabinets to create the TWD files. You talk about "lash" and that I must look to see how much. How do i do that? (for example on table axis, to see how lash it have) Our machine will be 2 years old in August.
Thankx for the reply

[Jason McDaniel]

Hello Marius,
Has this been an ongoing thing or did it just start to do it? To check mechanical backlash, you will need a dial indicator and a magnetic base to mount the indicator to. Place the the magnetic base onto the base of the machine and load the indicator onto the table drive. With the indicator loaded turn the dial to read 0. With the machine in the ready mode, push and pull on the table while watching the indicator. You should see the indicator move but it should always go back to 0. It will probably have a .001"-.003" backlash being it's two years old. Anything over .005" could be causing the problem you are seeing. If this problem has been ongoing then maybe it's a setting we can adjust in the control. If you would like you could call me here at Thermwood with any questions you might have. 1-800-221-3865

[Marius Gouws]

Jason, Good afternoon
I have taken photos of what out machine do, or so to speak does wrong. You can see it with the naked eye, like in the photos, when it cut dados horizontal across the table and it is then when the table has to move over that little bit, then it seems to be spring loaded it jumps past the point and then back where it should have stopped in the first place. Also like I have mention in my previous post the table does not accelerate and de-accelerate smoothly, that is visible in the second and third photo when it dado a cut for the back of an corner cabinet.(where axis 1 and 2 move together). Daniel say that it might be mechanical, if so how do I fix it, by replacing what?
The machine will be 2 years old in August, and I had a look at things we made more than a year ago, and if you look and feel than you can pick it up, but it is not as fare as noticeable as now. Seems as if it's getting worse all the time.
This is just pictures from one job, it looks just as terrible if I am trying to cut small to medium arcs. Only thing that help bit is if you slow the machine down to lets say 5000mm/min, but then the cutter burn up.

[Forrest Chapman]

Marius,

What size is this dado and what sized tools are you using? Also I had a shutter at one time in my machine and found out it was only the leveling bolts were loose in a few places. This caused the table to rock when the head swung to one side and sometimes I got a little whip. It could also be your collet is wore.

Forrest

[Jason McDaniel]

Marius,
It sounds like it is mechanical if it is getting worse. I would look at a few things on the table. Before you look at anything else make sure the timing belt is tight and not missing any teeth. Then:
1. The ballnut that rides on the leadscrew. This is the bearing that actually drives that table.
2. Make sure the ballnut flange has not come loose from the table. The flange is the part that the ballnut attatches to.
3. The thrust bearings in the end block. If you find the pulley that is turned by the servo motor, you will see the endblock bearing that supports the leadscrew. If the jam nuts have loosened up some, it could let the leadscrew rock back and forth in that block. If that is the case you could simply tighten the jam nuts back up.

It could be other things mechanically on the table but these are the most common. Send me an e-mail to sevice@thermwood.com and let me know the serial number for your machine and I can send you some pictures of the parts I want you to inspect.

[Marius Gouws]

Morning Jason
Tried to send you an e-mail but it came back undelivered.
Our machine number is : C40-482. I hope this is the number you are looking for.
Another things is that our control version (THM version) is 6.0.8.2. How to we upgrade to version 6.1.0.3 or higher, the reason for this is that I want to be able to do my profile cuts in control nesting all at the same time. The way I have to do it now is to nest and cut the MDF doors in Control Nesting and then have to single load them one by one in Profile Modler to do the profile cuts. Reading the Control Nesting help this can be done if we have version 6.0.1.3 or higher.
you can send me information to: gouwsie@mweb.co.za
thanks in advance

[Jason McDaniel]

Hey Marius,
Sorry about the e-mail adress. I left the r out of service. I will be sending you an e-mail as soon as I get all the information together.