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DIY Laser Cutter Project

Things

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Skip to page 8 of this thread to see the final and working revision :)

This project is also being documented on my website here: http://nqlasers.com/lcutter.php


Well, school holidays starting from today, so I thought I'd better think of a project to work on during the 2 months I have off.

A week or so ago, I ordered a 40W CO2 tube, which spawned an idea. A laser cutter/engraver.

Today I went to the hardware shop and bought most of the parts, though I under estimated the amount of angle aluminium I'd need. Theres about 6 metres of angle aluminium in the setup already, and a lot more to go.

It will be controlled by 2 (Or possibly 3) micro stepping stepper motors, that have 200 steps per revolution. These are controlled by an Arduino using a coordinate system, which in turn spin threaded rods, which will move the carriages.

It's still in very early stages, and requires a LOT more work yet, but it's nice to see it starting to come together :D

A proper PSU with analog modulation for the CO2 tube is going to cost me around $180, and optics (2 mirrors and a focusing lense) around $130, so it's not a cheap project, but far from the price of a premade laser cutter. I estimate the total cost to stay under $500.

The table is 1x1m total. Cutting area will be a little less, but still very reasonable.

Anyway, heres a picture of it at the current state:



I'll keep updating this thread as I progress, though it'll be a pretty long winded, but well worth it project :)

Cheers,
Dan
 
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TTerbo

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Re: My holiday project :D

cant wait to see it in action :D
now i need a project for the holidays :eg:
 
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Razako

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Re: My holiday project :D

Now this is a cool project. Can't wait to see how it turns out.
 

kiyoukan

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Re: My holiday project :D

i am going to suggest right now you stop designing that way.
It will work but you will encounter many many problems.
Build Your Own CNC Router Machine
Take a look at how they design the slides using skate bearings.
This allows for very smooth movement and less wobble.
Also helps you work out design flaws.
But GL and HF.
Also some reading search up an X Y vice.
That is a cheap way to make a laser cnc machine as all you have to do is connect motors and hang laser overhead.
Looking for my cnc controller.
you can pick up a good 3 axis controller for around 50-65$ better than the 30$ arduino controllers that you will need 2 of.
http://www.cncgeeker.com/index.php?main_page=product_info&cPath=1&products_id=1
http://laserpointerforums.com/f44/cnc-machine-diy-44968.html
Same as this but a laser and the third motor is not needed.
 
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Things

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Re: My holiday project :D

This method has been proven to work well, I have no doubt it'll be very stable once I add the remaining few metres of angle aluminium and another threaded rod.

I only need 1 Arduino, as I do not need a Z axis (Can adjust that manually), so only 2 steppers to run, then control the laser power.

I was originally going to go with a parallel port design, but I don't like the fact it has lower priority than everything else. I think it's better to do all the processing off the computer.

EDIT: I'll see if I can find a source of bearings, I may replace the wheels with some angle alu and bearings to ride on it.
 
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Things

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Re: My holiday project :D

Just reinforced the base a lot by adding angle peices in the corners. Keep in mind I'll still need to add something for the materials to sit in, which will add a LOT of stability.

EDIT: Here is the little assembly that will mount on each side of the X carriage to pull it along the threaded rod. The bolts are sandwiched enough to stop them spinning, just need to add a little glue or something to stop them from trying to move back and forth.

 
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Things

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Re: My holiday project :D

Alright, I think I'm gonna drop the wheel idea as I found a much better way of mounting the threaded rods. There will be 2 rods (with this setup)



On the X carriage, and just 1 threaded rod for Y.

Cheers,
Dan
 

Misellus

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Re: My holiday project :D

I've been building a 3 axis cnc router for about a year now (I quit during the coldest and hottest parts of the year...too uncomfortable in the garage). Mine is also controlled by an arduino with 3 homemade "brute force" stepper controllers (cost about $5 each to build) and can do microstepping. I can draw a schematic if you like but it's just 4 outputs from the arduino triggering 4 darlington transistors connected to the stepper coils and a resistor inline with each center wire of the stepper (my steppers are 6 wire). I'm using an old computer power supply to get the 12 volts for the steppers and 5 volts for the arduino. The arduino sketch is a g-code interpreter so you just feed 1 line of g-code at a time from the PC (several programs can do this).

How are you connecting the allthread rods to the stepper motors? I've never found a method that I really like. Originally I used set screws and a coupler, but they could come loose easily. Since my steppers have a + shaped shaft rather than smooth round, I cut a couple slits into the end of the rod and slid it over the + then used a bolt to tighten it in place. Works better, but the Z axis still comes loose occasionally.

Misellus
 

Things

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Re: My holiday project :D

Hey Misellus,

Thanks for the ideas. I'd love to see your Arduino code if you don't mind, I haven't figured out any software implementation yet. I have created simple code that allows me to move the steppers in X and Y coords, but nothing that'll work with a program.

As for the rods, I'll get a coupler machined. I have a friend that is willing to do it for me :)

I won't really have a Z axis, as you just turn the laser on and off, although I may add a little threaded rod and motor so i can adjust focus on the fly. I'll see where I end up.

Today I hot glued a stepper onto the threaded rods just to see if it'd have enough torque. It appears it does, however speed is going to be a huge issue. It took around 90,000 steps to move the carriage right across the table. At 200 steps per revolution, at a max speed of 60RPM, that calculates to around 6 minutes for the carriage to move right across the table.

I think I need some faster steppers :)

They cost a fortune though :(

Cheers,
Dan
 

Misellus

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Re: My holiday project :D

See attached for the code. I included both the original and my modified code.

I found it online last spring. It's the RepRap code that someone removed all the calls to heater and extruder. If you're using a standard STEP/DIR controller you can probably use it with minimal editing.

I modified it to work with my controller. I've not restored the axis min/max sensors and they are currently set to return positive no matter what. I ran out of pins so I either need to switch to a sanguino or a mega, or build an encoder to do it with fewer pins. I have a mega so will probably take the lazy way out.

Also, I don't know if you would be interested in used steppers, but I am planning to go to a local electronics surplus shop on monday or tuesday. It's where I bought the steppers for mine. I can check to see if they have anything you might find useful. Bad news is that you don't know exactly what you've found until you get home and can search the internet. I usually just look for the largest ones since that tends to mean higher torque. The ones I bought are 80oz/in and cost $5. I don't remember seeing any for more than $12. Do you have a preference for number of controller wires?

Hope it helps.
Misellus
 

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kiyoukan

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Re: My holiday project :D

these are the ones i use for mine.
4-LEAD, 1.8 DEG STEPPER MOTOR | AllElectronics.com
Mine were the same but without the gear. they have a good amount of power and move fast if you look at my thread you can see a video of my machine and pictures.
it could move about 20in in and around 40 seconds
That was at a slower speed you will need to adjust time timming on the steps .
As i can set mine using a real software to go faster than the motor or slow.
If you go to fast you will notice they will start to miss steps or vibrate instead of steeping.
Gl with this but i sugest taking a look at that cnc controler and using it. works with almost all cad software.
So you will have pc control cheap and fast.
Also to join them together there is a simple way.
Use a 1in bolt meant to connect to rods together and drill a hole threw it and the rod and slide a pin in. or just use glue. but make sure to drill hole still to let air out or you will have a hard time getting it to set.
 

Rafa

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Re: My holiday project :D

How much money did you spent for what you have ATM? Looks really cool! +1! Edit: Crap I can't +rep you again.
 
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Things

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Re: My holiday project :D

Thanks guys :)

@Misellus

Thanks for the code and info :)
As for the steppers, almost anything would be better than what I have now:



They only have limited torque and they only go maybe 60RPM before stalling.

@kiyoukan

As this is a long term project, I still have plenty of time to consider my options. Once I have the carriages and table built, then I can start figuring out the software side of it.

@Rafa

Thanks :)

The 40W CO2 tube cost me around $180 incl shipping on eBay. I have spent about $70AUD on hardware so far. I expect the total of this machine to be under $600 :)

Cheers,
Dan
 

Things

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Re: My holiday project :D

I've decided to use V bearings for the guide rails. They'll take like 2 weeks to get here, but will be a lot better than what I was thinking.

X carriage is now almost complete, except for the bearings. I'll get some pics a bit later.

Just bought 4.

Cheers,
Dan
 
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