DIY 80w Laser

[identernet]

Hi
I came across this site whilst researching information for building an homemade laser engraver/cutter. I have found it so helpful that I thought I would attempt to write a buildlog. I have never done this before so please be gentle with me.
I had already built a 4' x 6' CNC router so felt reasonably confident regarding the mechanics/controls. I used mach3 for this so intended to use it initially for my laser machine. Because there are no cutting loads on the cutter, this should be a lot easier build than my router. Just a big plotter I reckon and there is no Z axis to wory about
I manufacture wooden geared clocks but found that I was unable to make small gear wheels because of the minimum diameter of my cutting tools, about 3mm or 1/8". The laser should enable me to make small gears, although perhaps not as thick.

I have attached my some renderings of the design I have done in SolidWorks. The parts required for the chassis are currently being manufactured and powder coated. I have opted for an 80W tube, although at 1.6m, perhaps a little too long.
Anyhow too late now as I have received it from Coeltech in China (Ebay), along with the power supply, mirrors, mirror mounts, lens, cutting head, tube mounts. These all seem to be very good quality and I,m very impressed with them. They arrived in the UK 6 days after ordering them and nothing was broken.

As soon as the steelwork arrives I can get down to some serious assembly.

[bdring]

Looks very nice so far. What type of work area do you think you will have?

FYI: I use a lot of bits on my router below 1/8". I buy most from precise bits. For most of my cutting I use a 1/16" 0.50" DOC 2 flute bit. They last a long time. I have even cut 1/4" thk. 6061 aluminum with them..not designed for that..but works.

[identernet]

Hi
My work area will be about 800mm x 700mm. If I had realised how long an 80w tube was going to be then I could have increased the X axis substantially. Should have done a bit more research before doing my design although I shouldn't imagine I will need an area much larger.
It's very difficult to get good quality router cutters below 3mm in the UK. All the ones I have tried never seem to last too long before they break. I do need a shank length of at least 10mm though for the work I do. I find that I need to reduce my feed to a very slow speed to avoid breaking them. Gave up in the end and stuck to 3mm.

[identernet]

23rd July 2010
My steelwork arrived from powder coating and all bolted together nicely. Did it in the garden as the weather was so nice ( unusual in the UK). All the rivet nuts(M6) were fitted at this stage which will allow the 12mm MDF panels to be bolted to the frame.
I'll now put it together in my garage, fit the panels (that will give it a lot more rigidity) and level everything up. I intentionally built it light-weight so that I would be able to assemble/disassemble it easily myself. This was a lesson learnt from when I built my CNC router. I think I was speaking an octave higher for about a week after assembling that.

[Tweakie]

I can see this is going to be a very nice machine. Keep posting the pictures.

Tweakie.

[identernet]

I've now started the build in my workshop (garage). Unfortunately I already have a large CNC router which dominates the cental part of the available area. Because of this it makes distance photographs difficult/impossible.
The frame has been assembled and leveled but I didn't realise how far the floor was from being level. The adjustable feet only had 40mm of adjustment so I was forced to pack the back feet (what a great start) . The frame has been clad with 12mm MDF using M6 screws and 25mm repair washers so that I didn't crush the MDF. This has made the frame very stiff as I expected.
I've installed an IEC plug and breakout board at the right side of the machine and positioned the Y axis linear shafts.

View of the left side of the frame

This is the right side of the frame showing the IEC plug and breakout board.

An external view of the IEC and breakout board

An internal view of the IEC and breakout board

Whilst pondering the extraction side of the job I realised I had a brand new cooker/hob extractor unit from my kitchen fitting days. I butchered this and managed to extract an adjustable speed centrifugal fan, a light and a micro switch. This should work great and is very compact. I had to install it into an enclosure which I attached to the left side of the machine.

View of the cooker/hob extractor unit

The Y axis linear shafts were mounted to laser cut angle brackets so that they could be attached as modules along with the relevant bearings. This means that any adjustment would move all the relevant parts on that side (that's the theory anyhow). They have also been mounted using large "T" nuts underneath to give plenty of adjustment. Just realised I am limited to 5 attachments so will continue with my next post. I obtained the breakout board from a company called Routout Cnc a few years ago. I don't think that they do this item anymore, but they do one similar. http://www.routoutcnc.com

[bdring]

That looks great. That evacuation blower might work for some materials, but you will probably want to upgrade that in the future if you cut any plastics. Also, ideally the blower is placed outside the building or at least right at the wall so the entire system is at negative pressure and leaks go in rather than out.

Lasersafe1 did a great right up in the forum dedicated to the subject. At first I thought the idea was overkill, but because a true believer after cutter a lot of material.

Another thing, do you have more details on the PP breakout board. If you have a URL, edit your post to add a link to it. Hover your mouse overthe URL button when editing a post to see how to do it.

[identernet]

The next few photographs show the attachment of the linear shaft assemblies. I used linear shafts because I already had the parts, but I think I would use slides as per the X axis if I was to make another. They seem more compact, allow full support and appear to run a little smoother, but this is just a personal thought. Although these linear shafts have never been thrown about, I'm sure there is a slight bend in one of them .

Frame showing the left side linear shaft

Frame showing the right side linear shaft

Frame showing the T nut attachment

Frame showing the T nut attachment

Although the T nut arrangement looks a little crude, I found it great for overcoming assembly and manufacturing tollerances.

[bdring]

A slight bend can be a big deal on a laser cutter. If this causes the mirror to move up/down or left/right while the axis is moving, this problem will be amplified through the length of the beam after the problem. People have spent days trying to align the mirrors, only to realize a slight bend is making it virtually impossible.

[identernet]

Yes, I thought that myself. Will have to hope that I'm just imagining it. Have put a steel rule along it and it looks ok, but I can feel the linear bearings tightening up when I have the shaft in a certain orientation. I turn it 90 degrees and it disappears. This is almost certainly due to a slight bend in the shaft. I think I will replace it later as I can easily retract it.