Lowrider 2 does not respect the proportions

Hi, I’m Gianni
i bought a lowraider in december 2019

Now I have to do some precision work and I have noticed that the cutting measurements are not accurate.
if I draw a square of 15 mm x 15 mm the real measurements I get are 14.9x14.9.

Everything I carve is slightly smaller

Is it a firmware or edl lowrider mounting problem?
What adjustments can I make?
I use Estlcam and Repetier-Host as software.

I also plan to upgrade the firmware to the dual-endstop.
Do you think there can also be improvements in the precision of movements?

Thank you

I tend to look for the simple stuff first and I’d make absolutely sure the tool diameter was exactly what it’s supposed to be before looking elsewhere.

When you say “draw a square” are you using a pen? If so, in estlcam are you using the carve function vs part or hole? If you do a 30x30 does it come out 29.9 x 29.9 or 29.8x29.8?

Remove any issues with cutting inside/outside/on the line/ tool diameter. setup your router and accurately mark the spindle position, then command a move of (say) 100mm - does the spindle move exactly 100 mm? If so then your problem lies in the software cutting position/tool diameter, if it moves less than 100mm then your problem is (very likely) hardware related (lost steps/loose grubscrew/jumping belts)

I tried to draw different geometric shapes with a fine point pen.
With Estlcam I used Engraving -> Engrave centered along the shape

If I made 30x30 I have 29,87

Here’s what I say to myself anytime I encounter a problem these days: Ruling out user error is the most challenging and most rewarding issue to correct. It costs nothing but pride and dignity, but as soon as it is dealt with and rectified everything usually falls into place quite nicely.

I believe the belts can loosen slightly after a short break in. Might be worth checking them to make sure they’re snug. Does your pen mount have any play? That can easily throw off measurements.

Draw the biggest squares you can manage. If all else fails you can tweak the steps/mm. (Some will object to this)

To mitigate play or wobble in pen mounts I like a procedure where instead of drawing actual squares I write some gcode to draw an x at each corner. The pen is lifted up completely off the paper for each leg of the x to relieve any tension in the pen, each leg starts in the center of the x.

If you’re using a pen, this pattern generator from Jamie can help you narrow it down:

https://vector76.github.io/gcode_tpgen/

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No one else has said it yet - are your grub screws tight?

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