New CNC laser log

[WilliamD]

Well, I've been asking questions and gathering for awhile, and figure's it time to start the thread. I have a very sturdy and accurate 12" x 12" cnc table I'm going to convert to a laser head. I just received my 40watt sealed tube yesterday (in one piece ) and the powersupply and lens will be here today or tomorrow. I have the two gold mirrors necessary also.

The lens I'm using has a 2.5 inch focal length, and is a GaAs lens. I was told that it was just as good as the ZnSe lens, and for the price I was willing to take the gamble. Plus, I can't seem to find too many ZnSe lenses on ebay right now.

I will post pictures tonight when I get home of the tube and setup, and show you what I'm going to do.

Also, a little background. I converted the CNC table to use a HF trim router, and it worked well. The repeatability is amazing, and there seems to be no perceptible backblash when using a dial indicator. I'll have each axis move back and forth numerous times and it will still return to zero. I love the bishopwisecarver bearings and rail setup it uses. I'm going to emulate this for my larger CNC router. But I started a scrapbooking business with a partner (female,or course) and she had a lot of ideas for products. Well as it turns out, most of it's made of 1/8" hard board, and then acrylic sheet. Also stamps. So I started doing them on the router, but it was very annoying. The accuracy and speed were more than acceptable, but the hold down situation was awful. I have to use a ton of double stick tape, and then it's so strong I'll always loose 10% of whatever is on the sheet. So after researching, I knew a laser would be the best bet. There's only one other scrapbooking supplier I've found that uses a laser table as well. Most of it is die cut, but then you're limited on what you can buy. If a sheet took 30 minutes of run time, it would take an additional 45 minutes of prep time, removal and clean up time. With the laser I'll simply have to place the sheet on, cut, and remove. So I'm pretty excited. Plus, lasers apparently do very well with acrylic, which is were the bigger profit is.

After I post some pictures, I'll have a few questions for you guys. And I certainly welcome any questions you might have for me!

[Mat-C]

What is scrapbooking?

Have you considered a vacuum pump and a table full of holes to hold down the sheets?

Good luck with the conversion, looking forward to the pics

[WilliamD]

Scrapbooking is when you cut up pictures and paper and make an album out of them. Kind of like a keep sake thing. It's taken overcome women here on the west coast! My wife is pretty big into it, and practically every other woman I know. I would love to do the vacuum setup, but the pieces I make are too small and intricate to hold up to the router. That would have solved a lot of my problems (financially!). I figured out the tooling costs, and with each letter it costs about $.06 for the router. The laser costs about $.0002 cents per letter in tooling. Pretty big difference. Although, I could have bought 65 routers for how much I paid for one Laser! But the real savings is the time. This will be so much more faster and less hassle. Plus, the CAM will be much simpler. No more having to worry about tool comp, or picking the inside or outside of a curve. I will have to edit a post for MC9 to spit out the g-code I need. I'm still looking into that. But for what I want to do, I might just end up buying SheetCam. Don't need anything real fancy, simple 2D will work. I'm really anxious to get home, knowing all my packages have arrived! I'm certainly going to do a comprehensive list of materials, and all the factors required to cut them. I think there's too much mystery out there with that. But I suppose it's because there's a lot of factors that determine cut quality and speed.

[Mat-C]

Ah, that makes sense on the sticking down then... I'm still confused why you need a laser cnc machine to make a scrapbook... do you make up custom books for people or something? Sounds like a great idea though, if you are able to make it work.

[WilliamD]

OK, pictures as promised!

This is the power supply. Luckly no parts were jingling around. Seems to be in one piece!



This is the 40watt laser tube. It's about 40 inches long, and 2 inches in diameter. I thought the majority of the tube was the water jacket, but it seems it just an outside layer of the actual laser tube. I can see now why you would need a higher flow pump.



This is the lens I bought with it. I'm kind of disappointed, but if anyone can comment to the effectiveness of these lenses, I would appreciate it. I'm still in the market for a ZnSe lens, but well see how this one does with tests. It's 1/2" in diameter, so I'm a little worried about it taking in the whole beam from the laser. But I'm sure it will do for now.



And lastly, this is the CNC I'll be hooking it up to. I'll be taking the router and whole z-axis assembly off, but not before I machine some stuff I need to hold the laser and what not. I'm running a xylotex board, with 279 oz motors. I can drive it up to 600 in/min, but I keep it at 300 in/min rapids. I need to make a bearing setup for the top leadscrew, otherwise it can whip and bind sometimes. I obviously won't be cutting that fast, so I'm happy with the lower speeds. Also, the accuray and most importantly repeatability is way more than expected. It hasn't missed a beat yet. Also, the 279 oz are plenty powerful. I can't even stop the table when it's moving around. A lot more power than I expected! I can see how people drive the larger MDF cnc's with this setup.



I'll be shooting the laser beam down the what I call x axis. So the laser will be perpindicular to the machine. I'll have one mirror at 45 degrees to shoot the laser down the z and through the lens. Pretty simple. I'm going to make it adjustable, but it shouldn't be near as bad as some other setups. Of course, this machine is temporary. It's just to get the business going and taking off. I'm immediately building a larger CNC router, and a larger CNC laser table.

I'll be kicking it on and taking pictures and movies tonight! So I should have pictures in the morning. Plus a status on what materials I'm cutting, how much power it takes, and how fast they cut. I'm pretty excited!! (Oh, and wish me luck. Although I'm very careful around equipment, my wife is really worried I'll blind myself. But I have goggles and shields to protect me.)

[Mat-C]

Great, thanks for the pics
How are you going to align the laser and the mirrors accurately enough?
Are all the axes stiff enough that the end of the laser won't wander after being reflected round the intermediate parts of the machine?
Have you got some front-surface mirrors?
Good luck!

[WilliamD]

Yes, I believe the axis are sufficiently rigid. They are actually very ridgid, but I won't say it'll work perfectly until I try. You never know I suppose. As far as alignment, I'm going to atempt alighing a little red laser with the beam. Mostly just burn a hole, see if it's acceptable, and then have it burn a origin and boundaries. I know there's a lot more than can go into aligning but I only have one mirror to adjust, so I'm thinking it won't be that hard. I have a big mill to make some of the parts I want for the laser. I'm just looking to get it basically cutting, not optimized.

I need to rig up a couple DC relays to control the pump and air assist selonoid. I'm at school right now, and don't get out until 10 pm, so it'll be a loooong night. I mostly want to make sure I can get the laser working, and completely verify that nothing is busted. But I hope to have it up and cutting by the middle of next week. That's pretty ambitious though, so it'll probably be done by next Saturday. With all the orders we're getting, it needs to be done yesterday.

[WilliamD]

I NEED HELP! This power supply is a bit trickier than I expected. The laser tube is wired up (nothing to brag about ) but the power supply won't put power to the laser unless I use the TTL or CMOS or potentiometer. I've attatched some pictures on what I have so far, and would REALLY like some opinions. The directions are not very good, escpecially for someone like me. Again, I would REALLY like someone's opinion on what I need to do!

[CJL5585]

So far, every connection that has been made to the potentiometer is correct per the wiring diagram on the power supply.

The white wire should connect to both terminals 3 and 4 (WP and G) per the wiring diagram. At present it is only connected to pin 4. (G)

The low voltage side of the potentiomenter will be the side with the white wire and voltage should increase as the pot is turned towards the Red & blue wires on the pot. (In other words, the pot will work in reverse as viewed from the knob end.

Jerry

[WilliamD]

Thanks! Thanks! Thanks!

[WilliamD]

YEEEES! I have it up and running on its own. Sure enough, I just had to connect the other wire, and I could control it with the pot. Without the focus lens, the beam was about .14" at 4". Definetly creates a lot of smoke. Then with the focus lens, roughly 2.5" away, the dot size was about .01". These are rough measurements. It was crazy seeing the little dot of white light. I had to keep whatever was in front of it moving though, because it would burn through very quickly and start creating a lot of smoke. Speeds and feeds are VERY important I can already see. I am seriously impressed with how fast I can cut through things. I've already tested my 1/8" hardboard, cardstock and a thick cotton/poly cloth. It did absolutely marvelous on each one. I haven't even turned the power up half way. It barely needs to click on and it's cutting through. Definetly happy with the 40 watts! Also, I practiced with some acrylic. VERY small kerf, and left a glass edge. I can see why that is a popular thing to laser cut! Although, the stuff I was using definetly smells, but it's nice there's no smoke. Definetly going to setup a serious blower and filter for it. I'm just so excited right now!! My mind is racing with all the possibilities! I will definetly have pictures and hopefully proper sized video's soon. I need to work immediately now to get it setup on the CNC, but that won't be the hard part. Thanks again everyone for the suggestions and answers!

[CJL5585]

Originally Posted by WilliamD YEEEES! I have it up and running on its own. Sure enough, I just had to connect the other wire, and I could control it with the pot.

If you want to remotely control the laser tube via the software or breakout board, you can break the white wire between terminals WP and G and install an Off/On switch, a laser tube Emergency Stop Cutoff , or a set of relay contacts controlled from software, or other configuration.

I believe that is what the two circles indicate in the WP line.

Congratulations!

Will be looking forward to more posts.

Jerry