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<p style="margin-top:0;margin-bottom:0">Right. I think it's probably better to try the simpler approaches and seeing if/how they improve things before moving onto more complex solutions. I say we should get a proper bed and level it as a first step. Once we
have a level cutting surface, we can work on improvements from there. <br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" color="#000000" face="Calibri, sans-serif"><b>From:</b> hackspace-bounces@swansea.hackspace.org.uk <hackspace-bounces@swansea.hackspace.org.uk> on behalf of Justin Mitchell <justin@swansea.hackspace.org.uk><br>
<b>Sent:</b> 01 March 2018 11:18<br>
<b>To:</b> hackspace@swansea.hackspace.org.uk<br>
<b>Subject:</b> Re: [Swansea Hackspace] Laser cutter kerf</font>
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<div class="PlainText">On Thu, 2018-03-01 at 11:00 +0000, Andy Rush wrote:<br>
> I've made a few laser cut pieces recently, and as far as I can tell,<br>
> the beam's kerf is near 0.3mm at its thinnest, 0.6 at the widest. All<br>
> the dimensions are 0.6-1.2mm off what they should be on paper. I've<br>
> had a quick google around, and most places suggest that a laser<br>
> cutter kerf should be within 0.18-0.22mm at the thinnest part of the<br>
> cut. Are there steps that we can take to improve how accurately the<br>
> laser cutter cuts, beyond trying to to account for the kerf within<br>
> the original design by padding out all dimensions in the original<br>
> file?<br>
<br>
The bed is very likely not perfectly level, the main bedding sheet<br>
tends to get propped by pieces of scrap to an appropriate height for<br>
the material being cut, and may not even be at the optimal focal depth<br>
for you, depening what your doing.<br>
<br>
there are things we can improve that cost varying amount of time,<br>
effort, or money.<br>
<br>
1) Someone can measure and build a focussing aid<br>
<br>
this could be as simple as a cut/3dprinted depth gauge that you hang<br>
off the top of the laser head to physically see where the focal depth<br>
si supposed to be.<br>
<br>
or as complex as finishing fitting the alignment head we 3d printed,<br>
which has two line projecting laser to make a cross hair for lining up<br>
jobs, add a 3rd spot laser at an angle and it could indicate depth as<br>
well.<br>
<br>
2) replace the current bed with one thats actually level, perhaps a<br>
honeycomb type. There are lots of designs floating around for<br>
adjustable (either mechanically or electrically) ones that would let<br>
you easily change the focal point.<br>
<br>
3) improved optics, i have read claims that you can buy replacement<br>
focal lens that has a sharper kerf, but i dont know what the costs are<br>
like on that.<br>
<br>
<br>
4) if you care about accuracy of cut then you do always have to account<br>
for the kerf in your design, at least once you have a stable idea of<br>
what that value is.<br>
<br>
<br>
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