Preparing CAD work for laser-cutting
To reduce the time needed to convert your CAD files for laser-cutting
and/or engraving you can do the following:
- Your CAD file must be in any of the formats that CorelDraw V15 can read. This includes AutoCad, Adobe Illustrator, PDF and all CorelDraw formats up to and including version 15.
- Do NOT use white lines (these are invisible after importing in CorelDraw).
- Ensure that your CAD files do not contain doubly drawn lines.
The laser-cutting machine will dutifully cut those twice (or thrice, etc.).
This is a waste of time and the cut will become more charred with each
pass. Narrow objects may actually tilt slightly after the first cut and
then become damaged on subsequent cuts. In AutoCad this is
easy to fix.
- Divide your work in sheets that fit within 60cm wide by 30cm tall. This
is the size of the working area of my machine. All objects on a sheet will
be laser-cut from the same material.
- Please put each sheet in a separate file.
- Leave about 2mm between objects on a sheet and keep objects at least 3mm
from the edge of the sheet. You may put small objects inside holes in larger
objects if the bounding box of the hole is at least 3cm x 3cm. (If the
bounding box is smaller and the hole is cut before the object that you
put inside it is cut, the material is not securely fixed during cutting.)
- Lines that must be laser-cut must be the thinnest lines that your CAD
program can use (hairlines). Color can be used to set different power or
speed levels for the laser-cutting machine. This can be used to make
very shallow cuts for decoration (see below). Color can also be used to specify the order of cuts (to ensure inner lines are cut before outer). Use pure fully saturated colors for that (such as 100% Red)
and specify colors in RGB space (not CMYK).
- Thick lines, filled areas, texts, etc. are laser-engraved. This process
is very time-consuming. If you don't need things engraved; do not include
them in the CAD file you provide, or put them in a non-printable layer.
- Decorative lines can be cut by selecting low power and high speed. The resulting cuts will not go all the way through the material. This is much faster than engraved decorations. You will have to assign one saturated color to such lines.
- The width of a cut is about 0.1mm. If possible, avoid parallel cutting lines that are less than 1mm apart.
- Email me a one-sheet CAD file
that I can check for problems.
- Bring your laptop with your CAD program with you in case you have to fix
minor problems, or I can't import your CAD file into CorelDraw.
Selecting and preparing materials for laser-cutting
- I have 4mm MDF in stock and (approximately) 3mm Perspex (PMMA) in many
colors in sheets of 60cm x 30cm. Anything else must be provided by you.
- If you provide your own material you will guarantee that it does not
contain PVC. (Laser-cutting PVC generates Chlorine gas
which is highly toxic and corrosive; it could damage my heath and the
optics of the laser-cutting machine.)
- Laser-cutting wood, or MDF generates smoke. This smoke may stain
the wood near the cut. If you don't want that to happen, the material must
be taped with masking tape before laser-cutting. (I have suitable masking tape in stock.)
- If you have a choice between card-board and MDF; take MDF. MDF can be laser-cut at a higher speed and the result is much cleaner and stronger.
- Not all MDF can be laser-cut. Lighter colored MDF seems to give the best results.
- If you have a choice between Vivak (copolyester) and Perspex (PMMA); take Perspex. Laser-cutting Vivak causes headache inducing odours and I have decided that I will not laser-cut Vivak anymore. Perspex is a bit more brittle, but much cleaner to process.
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