How Should I prepare Files for Laser Cutting?

I have had an idea for a product that could appeal to model engineers, but would certainly appeal to a different audience. It would essentially be a simple kit of parts laser cut from a metal sheet, to be removed and hand finished by the purchaser. For obvious reasons I can't say exactly what yet, but imagine 20 - 30 small parts arranged on a sheet smaller than a sheet of A4, in 1/16" steel. The parts will be of similar size and complexity to 5" gauge coupling hooks, but in a range of differet shapes.

I am quite capable of producing a digital drawing showing the outlines of the parts, but a few questions:

• Is DXF a suitable format or can I use a pdf?
• Should I just show the outlines of the parts or ahouls I include the tabs that hols them in the sheet?
• If I do the tabs, how do i decide how big they should be?
• Should the lines be in a specific order, or will that be done automatically?
• Should I give the exact size of the parts, or the line the laser takes?

If anyone out there wants to give me an estimate of cost for a single sheet of parts, and for batches of 10 and 20, please pm me and I'll let you have my email.

Thanks

Neil

Have you tried Malcolm High at "Model Engineer's Laser" ?

DXF is probably most widely used for transfer to laser or water-jet , file should be a plain sheet (no border or info boxes), include 1 dimension value as a double check that it has imported correctly into the CAM software. Obviosuly (?) make sure scale is 1:1.

I can guess at your other points, but it would be better for soemone who knows for sure to advise you.

Another thought - those offering a laser cutting service will likely have automated nesting software that they use routinely. Though there might be some cost, it could save a lot of your time, and give better packing (less material use).

1. Use DXF

2. Depends if the location of the tabs is important, ie, not in certain areas for aesthetic reasons. Presumably the parts will be removed by twisting rather than cutting.

3. I'd make the tabs as small as possible.

4. I'd leave the lines to be selected automatically to minimise material use and cutting time.

5. Outline of the parts; you don't know the cutting parameters and hence the width of the cut.

Regards,

Andrew

I assume it's quite important to be clear which bits you want to keep, and it's not just fancy holes in eth sheet

Neil

Simple answer is use a DXF file.

Talk directly to the people/company that are going to do the cutting (not an agent or go between).

Laser and Waterjet (dearer) can and do produce accurate predictable results but there are little details (nuances really) that if allowed for, can make the product (and your life!) a bit easier.

Depending on the material thickness, there may be a divot at the start and end of a cut that without preparing for, might end up just where you dont want it.

You also need to think about materials, if the laser cutting company are supplying and they normally make heavy engineering parts where the surface finish is going to be powder coated, your parts might end up unsuitable for cosmetic reasons.

If the material you are going to use has a directional finish (say its brushed SS) then the orientation needs to be indicated on the DXF.

Ian P

Edited By Ian Phillips on 04/09/2013 16:55:34

Another couple of points

In my experience your DXF should represent the finished outline of your parts, the company will make allowance for the width of the cut.

The finished surface of the cut edge is at a very slight angle, its hardly noticeable on 1mm sheet but needs to be allowed for on say 12mm stock. Actually waterjet can produce virtually square edges, but it costs more!

Ian P

I've just used DXF when I have had things water jet cut and given one or two overall dimensions

I would leave the tabs and layout to the cutters, their software will arrange the parts and place the tabs. unless you don't want them in critical areas.

Just the outline, the cutters will make adjustment for the width of the cut, Not sure if the Lazer cutting can be done to different grades but with teh waterjet you can have about 5 different grades of cut.

Your part will be cut from 1.5mm plate to allow for that in your design not 1/16" or 16swg

Thanks for the pointers - so I should just create all my outlines, arrange on the sheet and export as DXF - then see what a supplier makes of it!

I don't think it's giving anything away to say that surface finish and thickness will be of minimal importance for this application, in fact 0.5 mm sheet would, strictly, be best but it would not be strong enough!

Neil

With Jason on that.

Ask the company for their input, but specify everything.

Dxf file of profile with or without tabs, your preferred layout (in dxf), at least 1 dimension as there are often scaling problems when your dxf is read by their equipment and most of all don't just say mild steel unless you want the cheapest, cr*ppiest steel there is (they will quote for the lowest price possible).

Put your files on a memory stick and they should be able to run through your plans as you sit with them at the pc.

Trevor