Author Topic: Laser Cutter  (Read 10041 times)

Offline PK

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Laser Cutter
« on: December 22, 2015, 06:03:27 AM »
This is, strictly speaking, not a hobby build. We own and run a small business that designs and manufactures electronic devices, but we do build a lot of our own equipment, and we do it in the same way, and on budgets in the same order of magnitude, as the hobbyist projects.  So I hope there's something interesting in this for y'all.
We started out buying a 50 Chinese W laser cutter when we got a price for cutting some rubber gaskets that was almost the same as the purchase price of the machine.

The first two jobs we ran paid for the machine and we were off!

Over the years we upgraded most bits.

We took the tube and power supply to 120W

Blew up and upgraded the DSP controller (these lasers have magic boxes that do the motion control for thinkgs like raster engraving)

Added little boards to do things like turn the air assist on and off automatically.


As we started using it more and more, the 'pond pump in a bucket' cooling system got upgraded to a 'pond pump in a garbage bin'
and finally a 'Hacked portable air conditioner' which we ran today, all day, as the ambient temperature hit 40deg C...

(We subsequently removed the strap and installed the back cover)

Anyhow, things progress, and we start buying materials in full sheets to save some money, but cutting these sheets up is a PITA, so we start lusting after a full sheet capable laser....
We ended up compromising on a 1.8m x 1.2m laser gantry kit from LightObject http://www.lightobject.com/XLE-18001200-XY-Stages-complete-kit-for-DIY-CO2-Laser-2-yrs-warranty-P739.aspx
and our usual construction method of welding together laser cut steel.

The steel for that frame, laser cut (with all the bolt holes) and folded, cost AU$300.  We reckon that makes it hard to beat as a construction technique.

There's a big vacuum table under there for holding down big sheets of cardboard.
I'll try to get a few more pics together tomorrow.

Offline Joules

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Re: Laser Cutter
« Reply #1 on: December 22, 2015, 06:57:03 AM »
KEEP POSTING, I don't care it's commercial, what a great build.  I keep looking at the little Chinese lasers, but always find something else to fritter my money away on.    :doh:
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline raynerd

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Re: Laser Cutter
« Reply #2 on: December 22, 2015, 02:44:53 PM »
KEEP POSTING, I don't care it's commercial, what a great build.  I keep looking at the little Chinese lasers, but always find something else to fritter my money away on.    :doh:
yea same!!

PK - lovely looking premises/workshop/office you have there. Looks similar to the commercial clockmakers workshops I`ve seen - always wanted to create something similar!

Keep posting, great thread.

Offline PK

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Re: Laser Cutter
« Reply #3 on: December 24, 2015, 06:56:32 PM »
OK, so lets take a step back then.
Having purchased the original machine, we spent some time  building things like vacuum tables.


These come in handy when cutting stuff like cardboard


We also added a few extra sensors (which the control electronics had inputs for but didn't come with the machine). The most important one was an air flow sensor to the cutting air assist line.  Why is this important you ask???

When cutting flammable materials (we make self adhesive foam gaskets on this machine) the flow of air through the nozzle blows out the flame, just like blowing on a candle. When it stops blowing out the flame....


It wouldn't have been half as bad if the intern running the machine hadn't just stood there watching it burn with a fire extinguisher 2 feet away. I only got to it when the smell reached my desk!

In the end we just replaced the belts, cover window and mopped it out....

After about three years of daily hard use, the tube started to show a loss of power. A replacement tube was priced at AU$90+shipping, but these tubes are only of average power and quality. Besides, why buy a cheap 40W tube when you can buy and expensive 120W tube!  Well, it made sense to me at the time.... You sort of had to be there I guess...

So the 120W tube and power supply arrive and we neatly fit them to the machine with some PE mounts we made on the router and little bit of Al plate. You can hardly notice the upgrade, she's a bit of a sleeper..




As I've mentioned elsewhere, once you clear about 100W, a CO2 laser will start to mark metals directly.

It's a little dependent on how shiny the surface is, so a bit of tape over the top, or a light spray with paint will often be required... it is quite slow though, so it does pump a bit of heat into the job..

We ran the unit in this trim for a few years, making minor mods along the way. The only significant one is the refrigerative water chiller put together from a portable air conditioner because I wasn't going to spend the AU$1500 everyone was asking for a 'laser' coolant chiller.

There was little more to this than bending the lines going to the condenser so that we could shove it in a plastic jerry can full of radiator coolant.

I should stress that the hobby user will NEVER need one of these. All the Chinese lasers come with a pond pump and instructions to sit it in a bucket of water. This is entirely adequate for cooling any sealed CO2 laser used for less than an hour at a time...

A side note, you may have noticed that we have two laser cutters on the bench there. We bought the second one because the software that came with the first didn't support engraving sequential serial numbers on successive jobs. We would have to put 10 parts into the laser, then sit at a computer and manually change 10 text fields, send the job to the machine, run it, rinse and repeat. This got old quickly. The fix was to buy a cheap little laser, IIRC I paid AU$699 landed for it, and give it a brain transplant.


Back to the build
We actually started out by making the vacuum table. We wanted to be able to process full sheets (1.2m, x 2.4m) without cutting them. The working envelope of the laser is 1.2m x 1.8m so we decided to flip the table around and make holes in half of it. That way we could cut half the sheet at a time, then just pull the whole sheet forward and do the other half.
Now the little vac table at the top of this post looks a bit dinky, but it has more than 300 drilled and countersunk holes in it, all marked out, punched, spot drilled then opened up with a step drill. No way was I doing that for over 2000 holes.. (yes, that's 2000 holes folks!).

So onto the CNC router it went:

With the counter sinking, it still took about 3 hours to run the job....

After that we just built a box frame for it and called it done.

The next piece of the puzzle was a base for the machine.  There was much head scratching before I read an article about IKEA making furniture out of cardboard.....
I don't have a lot of pics of this stage (the young bloke has some on his phone I think) but we went out and bought some 6mm plywood and cut this core on the router.

We put 2 sheets top and bottom and got it within 1mm with a laser level. The whole thing is held together without a single screw or nail. Just using polyurethane glue. I'm not a little guy and I can stand on this 2.4m x 2.4m table and it feels rock solid.


So that brings us, more or less up to date.

We cut a hole in the back so that we can mount the electronics on a removable plate.


and I got a coat of primer on the steel yesterday,


I'll put some more pics up when the paint is on.
Cheers
PK

Offline PK

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Re: Laser Cutter
« Reply #4 on: January 08, 2016, 07:31:03 AM »
Over the break, I set myself the goal of getting some paint on the bodywork of the new laser. I mean, how hard could it be right?
I'm quite fond of the paints with epoxy in them. They produce very hard wearing finishes. The only problem is that they take about 5 hours to get to touch dry. This means that any overspray is gonna stick to whatever it lands on!
Having had some bad experiences in the past, and given that our spray booth is about 400mm square, I decided to apply the paint with a microfiber roller.

See below, but it sort of came out sort of OK....  Sort of...
I spent a couple of days trying to convince myself that this finish was perfectly acceptable for a work machine.....awe, who am I kidding?  Why have a mostly crap finish when, for only an additional week, countless hours of sanding, and another $50 in clear coat, you can have an only partially crap finish?

Why I didn't just send it out to be powder coated will remain one of the great mysteries of my life....
In any case, its' done now and we can move on..


Offline Brass_Machine

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Re: Laser Cutter
« Reply #5 on: January 08, 2016, 09:55:49 AM »
Hi PK,

Please keep posting on this. Many of us hobbyists, balance on the hard end of being semi commercial in the things we do. It is always nice to see how someone does it full time. Plus, we can either incorporate ideas in our own builds or provide suggestions and help to you as you do yours.

What kind of things do you design and manufacture?

Thanks!

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline PK

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Re: Laser Cutter
« Reply #6 on: January 08, 2016, 11:50:32 PM »
Hi PK,

Please keep posting on this. Many of us hobbyists, balance on the hard end of being semi commercial in the things we do. It is always nice to see how someone does it full time. Plus, we can either incorporate ideas in our own builds or provide suggestions and help to you as you do yours.
Sheesh, don't get too impressed. We're just hobbyists with cash flow.. I learn *LOTS* from forums like this and derive significant motivation too. I just worry that some of the ways we do things now may not be relevant to some because we took the 'screw it, just throw some money at the problem' approach.

Quote
What kind of things do you design and manufacture?
So there's two sides to it really. The money side is industrial electronics. We do both custom projects http://www.caswa.com/work.html a current example of that would be our SmartCamp project where we are building a networked RFID door lock system for mining camps that also manages the air conditioning systems to save power.

And we make some small volume electronics, mostly to do with remote monitoring and control of overhead cranes. Although AccessPack is a bit more generic. http://www.soledigital.com.au

The other side of things is my rocketry hobby, which is where the CNC machines were born. http://www.caswa.com/cncathome has some early cnc stuff.



« Last Edit: January 09, 2016, 08:31:48 PM by PK »

Offline PK

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Re: Laser Cutter
« Reply #7 on: March 29, 2016, 05:17:08 AM »
We're making slow progress. This is one if those 'figure out how to solve the next problem, order parts, implement' iterative projects...


Axii are installed in the case.


Wiring up is progressing.


Vacuum blower for the table arrived.


I figured out that the lid was going to weigh about 30kg and needed to open higher than anyone could reach......

So the design now incorporates a pneumatic lid lift. Bought the 75mm ram, modified the base to include a pivot. The grey arm is a weldment. Just waiting on a tie rod end to get here....

The plan is to use 1" bar between those pillow block bearings and add a gas strut or spring at the other end if needs be.

Offline Joules

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Re: Laser Cutter
« Reply #8 on: March 29, 2016, 08:32:05 AM »
I can see how the rocketry would get you out of a hole fast...   :lol:

WHOOOOOSH......  PK has left the mine.

Nice updates on the build.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline tom osselton

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Re: Laser Cutter
« Reply #9 on: March 29, 2016, 02:19:40 PM »
Watching with interest!  Thats how protospace got their laser donated after a fire in it.

Offline PekkaNF

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Re: Laser Cutter
« Reply #10 on: March 30, 2016, 03:32:54 PM »
Keep posting. Although I have no immediate need for laser, I'm reading all this with a great interest. I like iterative projects :wave:

Pekka

Offline PK

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Re: Laser Cutter
« Reply #11 on: March 30, 2016, 06:36:32 PM »
A laser cutter is a bit like a lathe in that you buy your first with some preconceptions of being able to make some simple parts, 5 years later and it's running a filing machine, filament winding and you have a 13 way tailstock tool holder that includes parts from a spirograph set..

We bought our first machine to make one simple part. Now we do all sorts of crazy stuff in our machines and we do a LOT of it....
Yesterday I made some rubber stamps to correct a silkscreen on a PCB. Last week we tried using it for soldering (it worked quite well).
We engrave marks onto stainless, mark tools, make complex cardboard boxes, front panels for electronics, the list is endless. I highly recommend them as a tool....

Offline PK

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Re: Laser Cutter
« Reply #12 on: April 12, 2016, 01:02:22 AM »
We're plugging head.
Last week we welded up the frame for the top lid.
On the weekend I made some clamp arms to go over the 25mm SS axle and transfer the opening torque to the lid frame.
These got installed today and with a bit of fettling, it works!



The jury is still out on whether the clamps will grip well enough to lift the frame and the big sheet of acrylic that's going on top of it, but we'll cross that bridge when we come to it....

Offline PK

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Re: Laser Cutter
« Reply #13 on: June 23, 2016, 01:26:11 AM »
Bit of an update
So most of the recent effort has been to complete the 2nd 80% of the project and we've just about done it.


The electonics and pneumatics are all in and tidy.


Lots of little details like 'How are we going to connect the coolant to the thing?' are done:


The touch switches for the vac table and pneumatic lift are done and (after more fettling than I was happy about) work well.


We did an inital rough alignment with this

shoved up the spout of the head shining back on a retical in the tube mounts. This let us get the beam parallel to the axii (which is the most important bit). After that we just translated the tube in Y and Z until the beam came out the nozzle.  Hmm, this sounds easier than it was. The beam path is nearly 3m and it took a solid haf day to get it dialled in...

We spotted fairly early on that the lid opening ram flexes the whole steel structure so much we were never going to hold alignment with the tube mounts fixed to the enclosure. So we laid up some fairly massive carbon fiber supports that allow us to hang the tube off the optical platform.

You can just about make out the aluminium mount we made for mirror #1 that allowed it to be simillarly mounted.

Finally we painted and stuck the lid on.



So now there's only the things we don't yet know we got wrong to sort out. I suspect that will be a long ish process. But we're not too stressed about it...

PK