Messages

1

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 03:11:43 PM »

ok thank you for the suggestions,

tried to cut 49mm cirkel

inner one Y48.7 x48.65  45degreo 49mm
outer one y48.5 y48.4    45 degree 48.8

this is whitout backlash comp.

i think there is a compination of  backlash and deflection going on here.  i just redid my my step settings measuring off the gantry with my dial indicator and it's dead on. but if i touch it slightly i can se neadle deflection and if i push some there is no problem getting the nedle move +- 0.3-4 mm


I

2

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 11:31:55 AM »

Yes, i have seen that.  I have checked my grub screws and they are as tight i can get them. I had problems with flat spotting like he mentions and that was because of one loose screw. But that is fixed now.

With backlash correction on,  the circle looks round now, but with the noticable jump each time it corrects itself. I'm using wery shallow cuts 1-2mm and feed rate of 1000

3

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 11:03:32 AM »

just to clarify, when i said that i can se the router jump, it's the hole gantry moving. if i hold on to the gantry you can feel it's the steppers making a quick change.

4

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 10:21:24 AM »

ok, so this is my result

the original circle  is now 49mm measured on  the x and y axis, and 49.4mm in the 45 degree angles whitout backlash comp.  
with backlash comp it is 49.4mm on all dimensions, but i get a small ridge just where the compensation is happening. and i can se the router is jumping right when its making the adjustment.

running the same program twice doesn't change anything.

i have adjusted the steps some from when i first started and used a dial indicator for measuring.

yes this is a hobby machine Openbuilds OX, my cutter is brand new. and i only make 1-2mm deep cuts in mdf right now when i try.

I will try to make a circle in fusion with a very light finnishing pass.

5

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 10:02:23 AM »

yes i think tool deflection might come in here also,  will try as you suggested

6

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 10:01:38 AM »

Ok, thank you.

played with backlash and that definitely helped but in (0.47mm for x and y, measured with dial indicator giving x-10, x0, x8,x0 ),  but when i try to make a circular pocket I'm getting a small ridge right when it changes direction on x or y

7

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 06:14:27 AM »

initially i tried make the circle in fusion 360 and had the same results. With fusion doing the tool comp.

8

General Mach Discussion / Re: oval circle

« on: December 18, 2016, 05:55:54 AM »

Thank you for your answer.

Changing from g40.1 g40 doesn't change the Dimensions.

if i try the set steps per unit wizard  and ask for 100mm i the lengtht is correct in both x and y.
I tried to make a 50x50mm Pocket With the mach wizard and it turns out square but only 49.8mmx49.8mm 

9

General Mach Discussion / oval circle

« on: December 17, 2016, 01:35:56 PM »

Hello,  New to this forum and the world of CNC and Mach3.

I'm trying to gut a test circle of 49mm but it turns out slightly oval,  to eliminate as much as possible i've made the circle in the mach3 wizard.

when i measure the circle it is only 48.5mm on the Y and X axis. but when i meassure on 45 degress to x or y it is the correct Dimension.

What am i missing or where should i look to correct this?

here is the g-code

(Code by Newfangled Wizard, 17.12.2016)
(Version 2.86)
(Program Posted for Wood )
G0 G49 G40.1 G17
G80 G50 G90 G98 
G21 (mm)
(***** Circular Groove/Cutout *****)
M6 T7
M03 S24000
M9
G00G43 H7 Z1
G00 X20 Y-2.25
G41 P1.5
G01 X22.25 F1000
G03 X24.5 Y0 R2.25 F1000
G01 Z-0.5 F500
G03 X-24.5 Y0 R24.5
X24.5 Y0 R24.5
G00 Z1
G03 X22.25 Y2.25 R2.25
G40
G00 X20 Y2.25
M5 M9
M30