Bumps in laser cut curves

[AvroraTut]

1. Hi guys
I keep having this issue of bumps in curves of letters designs, what ever it is..
laser cuts perfectly, works great, just get these bumps all the time.. any Ideas!
I output evrything from CorelDRAW to a DXF file.. I am very apt with vectors and know the vector lines are not the issue.

[AvroraTut]

IMG_0030.jpg (8.82 KiB) Viewed 2371 times

[Ccwjciafr]

You really need to list your equipment in your signature in order to make it easier for people to be able to help you.
his is a stab in the dark, but if you have a Chinese laser that is producing the problem, it is very common for the set screws to come loose on the pulleys for the axis drive belts that will then sometimes cause a problem similar to the one you show. The most common culprit is the pulley(s) on the shaft for the Y axis usually located near/underneath the laser tube. My laser has two set screws per pulley so you need to fully rotate the shaft to fully check things out.
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L3

[kanaedas]

If the line is perfect in CAD, exports clean (no crazy amount of sub-curves with crazy edges), and loads great in the control software, then it's the movement of the moving parts whilst in production.
It looks like the machine is either vibrating, or the head is vibrating as it moves along the path.

[AvroraTut]

Thanks Guys
the machine is a Chinese machine SIGN CNC dual head laser 1.5 mtr x 3 mtr.. one 60 watt head and a 160 watt head.
In the example above the machine is travelling at 5mm per sec.. very slow..
The odd thing about this is, it is in the same place always the same on curves.. The vectors are very smooth so that is not the issue.
if it is loose pulleys, wouldnt it be random.. I can cut the same circle many times in a row and it will be identical overtime..
Thanks..