Saturday, May 15th 2010 - 3:28 PM

Here is my new venting system. The flow is directly across the work area so the smoke basically disappears.
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This should improve things.

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Saturday, May 15th 2010 - 7:42 PM

I couldn't find details on how thick the alum is. It would definitely be safer. I don't know how easy it is to work with. Do you know the price?

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Monday, May 17th 2010 - 4:57 PM

I assume that would be for etching. It might be hard to detect the distance exactly at the laser spot. How acurate are those distance sensors for spot size? The sensor would have to shoot at an angle to avoid the laser and that might throw off it's accuracy. Hitting a surface angled towards or away might throw the thing off too.

I had an idea a while back about two laser pointers aiming from the each side. They would manually adjust to where they converge to one dot at the exact focal point. Any time you see two dots, you are out of focus. Something like a Wii remote could be used to auto focus the table.

I was also thinking the other day that it could be done in software. Say for example you wanted to etch on a wine glass. Even if you had a rotation thingy, the wine glass is not at a constant diameter. You could program the table to compensate for it in software based on the geometry of the part.

You also have the issue of the beam not hitting square to the surface when the surface height is changing quickly. That might degrade the image and might need to be compensated for in power.

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Sunday, May 30th 2010 - 11:55 PM

After about a 1000 requests, I have started making some kits. There is a page here detailing the kits.

http://www.buildlog.net/cnc_laser/kits.html

If you want any parts, please email me at bdring@buildlog.net. Please don't use the forum for kit requests.
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Wednesday, June 2nd 2010 - 3:20 AM

I am working on a comprehensive Bill Of Materials. This will boil everything down to a basic shopping list.

Of course I decided to write my own web based ERP system to enter and maintain it...( never take the easy way out)

It should be ready in a few days.

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Saturday, June 5th 2010 - 2:20 AM

The Bill Of Material feature is working now. You can check it out here.

http://www.buildlog.net/cnc_laser/erp/bom.html

This is a database driven Bill of Materials. It is not 100% correct or complete yet, but it is easy to change and maintain. If you see any problems let me know. I know that there are a lot of missing supplier part numbers and prices. I need to take the time to enter those.

I was actually quite surprised how cheap the Misumi framing is.
http://www.buildlog.net/cnc_laser/erp/b ... rtNo=FRAME

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Saturday, June 26th 2010 - 3:10 PM

I wanted to get a dedicated fire extinguisher for for the laser, but I kept forgetting to pick one up at the store. I mounted it directly to the side of the enclosure. It is ABC (and hopefully "L") rated.

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Sunday, June 27th 2010 - 4:56 PM

It just for piece of mind and it looks kind of cool. Most people who see my laser ask me where the fire extinguisher is.

I saw this sign a while back. I took me a while to find the image. The one I saw was better because it showed the laser. This one just shows the sign. Obviously there was a very recent fire. Just for effect, I would singe the lower edge of the sign a little.
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Sunday, June 27th 2010 - 5:04 PM

A couple people asked me where I got the hinge. I took this picture at Menard's. I am pretty sure this is the one I used. There is a nickel plated one (mine) for about $9 and a stainless steel version for $28.

I used M3 flat head screws because this allows keeps the screw heads from contacting each other when the hinge is fully closed. I did not use all the holes, but it is important to use the outer most screws on both sides because the gas spring is under a lot of pressure when the cover is closed and tries to bend the hinge if there is no screw close to the edge.
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Saturday, July 17th 2010 - 4:04 PM

I finally got the motors I ordered. I ordered them over 2 months ago. This was my first adventure into buying directly from a manufacturer in China. I will probably do a blog post on the adventures of buying them, but here is a quick overview.

These were custom built to order. They do not stock them. This method lets you pick and choose from all the features and get exactly what you want, but there is a big lead time as they get the parts and schedule production. The prices are very good if you order in a decent sized quantity. There are a lot of other costs that really add up though. Shipping is very expensive, especially for heavy stuff like motors. There is also the cost of transferring the money. There is also the risk factor. Many people never see their parts or money. You need to pay all or some in advance so that is a risk. If you can establish that it is a actual, viable company, and your contact really works there that is a big start.

I am going to sell the motors for just a little more than the whole endeavor cost me. The price should be better than you can get anywhere else, especially if you compare the features. If I sell all the motors in a reasonable time, I might make a much bigger order to really get the prices down.

I have detailed drawings and step files of the motors on the drawings page.

The smaller NEMA 17 motors are 0.9 degree step motor. This gives really high resolution and smooth motion. On my laser they could do up to 4000 dpi if you run in 1/16th step mode. I don't think the mechanics are that accurate, but, who knows, it could help with grayscale.

Check the kits page for details.
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Tuesday, July 20th 2010 - 3:02 AM

The X travel is about 27". The Y travel is about 16". The Z can move a little more than 8". The actual usable Z is less because of material thickness and focal length...maybe about 6.25" usable.

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Wednesday, July 21st 2010 - 11:27 AM

Thank you...fixed

The link was pointing to the wrong folder. The link on the home page was correct and still working. That is the one I tend to use, so I probably would not have caught the problem myself.

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Friday, July 23rd 2010 - 2:10 AM

I started playing with a remote control for my laser when used in Mach3 mode. I wanted to try programming my new phone. Hopefully it will prove useful. I don't get much time to play with things like this so it will be several weeks before it is done.
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Saturday, July 24th 2010 - 12:05 AM

I have added kit references to the BOM. The row in the BOM is green if the part is in a kit.

...as always click to enlarge
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Tuesday, July 27th 2010 - 2:42 PM

We had a huge storm over the weekend. We got about 9 inches of rain in a few hours. That was more than the basement (laser workshop) walls could handle. I got about 1/2" of water everywhere. No expensive stuff was ruined, but the rug had to be torn out and an MDF bookshelf and entertainment center.

Everything is up in the air (literally) until I get this sorted out. My bigger, woodworking/metalworking shop in the garage is unaffected.

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Tuesday, August 3rd 2010 - 12:19 AM

Robert asked about my terminal block parts. These are all Altech parts that I bought at Allied Electronics. Below are all Allied part numbers

black (line), white (neutral), and green (ground) blocks...6 of each (I did not wire to them all)
502-0797, 502-0795, 502-0801



I used jumpers to connect each color together
502-3222 (manually cut down to 6)



I used separators between the colors. 502-3210



1 end stop at each end 502-0211

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Sunday, August 15th 2010 - 3:59 PM

Good question. you are not the first to ask.

I started the project with a bunch of parts left over from a wood router that was replaced by a bigger one. This included 3 Nema 23 motors. My first iteration of the project used these motors. As I refined the project, wanted lighter and smaller motors for the XY Mechanism so they were replaced with NEMA 17s. I did not have weight or size issues with the Z so I left it at 23.

I should look at changing that one also. Maybe I could put both footprints on the motor mount. I will look into it. Maybe I could use the same belt pitch as the XY too.

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Sunday, August 15th 2010 - 5:36 PM

I added a second pattern to the Z lift motor plate for a NEMA 17 motor. This will get all the motors to be the same size. On this version I think I will use MXL belt and pulleys. I geared it down 2:1 so the motor should have plenty of power. I'll order the parts and give it a try. I will probably time the install with the MakerBot upgrades. Note: The belt does not look aligned right because it is still on the old Nema 23 parts which are hidden.
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Sunday, August 22nd 2010 - 7:27 PM

In preparation for the 3D printer head I am adding, I upgraded the Z Axis to improve it's smoothness. Previously the table ran up and down on leads screws only. This worked fine for adjusting the height. But the table would shimmy a little due to some lead screws not being perfectly straight. This is not an issue for laser cutting, but it will show up as vertical imperfections when printing.

I added some Misumi 20x80 vertical extrusions with v track and v groove bearings.

I also decided to switch to a NEMA17 motor and MXL belts. This will make all of the motors, belts and pulleys common. I decided to do a 2:1 ratio for more strength by making the motor pulley 18 tooth and the lead screw pulleys 36 tooth. The 36 tooth bigger lead screw pulley probably removed the requirement for folding back the belt on the pulley, so I removed all those extra bearings.

I had my digital camera ride the table up to show it's smoothness. The clicking is a non straight lead screw, but it does not affect the smoothness.
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Sunday, August 22nd 2010 - 9:08 PM

I don't have any issues anymore. Even ACME thread would still need a track to meet the stability I have now.

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Monday, August 23rd 2010 - 1:28 AM

The other buildlog has more details. I need to figure out what goes on what buildlog

Adjusting is very easy. It is done before attaching the z slides. I used the gantry as a reference point. I raised the platform close to the top. I then measured down from the gantry from the highest corner with my caliper. I then raised each corner up to that point by rotating the t nuts up. You lift the corner so the t-nut is free to rotate. This will get you to with 0.013" worst case. (1 / 18 tpi / 4 t-nut points). If you want to tweak out the last few thou you can loosen a pulley from the rod and spin it a little. I got it to within about .004" and left it at that for now. That is pretty good over 2 feet of width. You might need to repeat the process a few times. If you measure the height as close to the rods as possible it is less likely to change. Then attach the z slides. They just prevent XY motion.

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Thursday, August 26th 2010 - 3:44 PM

I get asked all the time if there are detailed build instructions. Right now the answer is basically, no. Some assembly drawings have some build information. Other than the buildlog itself and the forum, that is it. I have about 20 things on my project todo list and time for about 4 of them. Some people have offered to help, but no organized effort has started. I can help, but not do the whole thing.

I was thinking about starting a wiki for this. This way anyone could contribute and it would stay more organized than a build log. Does anyone have any recommendations for good wiki software. I would like it to be free, open source, self hosted and popular enough that it won't go anywhere soon. MediaWiki comes to mind...is that a good choice or overkill?

The wiki could also have some general info sections.

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Sunday, August 29th 2010 - 5:34 PM

I installed a Gecko G540 in my laser. See my blog post for a review of the product and install. I wanted a four axis for some experiments with atangentail knife cutter and I wanted a smoother driver.

The interface on the G540 is not ideal for controlling the laser enable quickly, so I made a breakout cable. I will be adding to the cable, but this will do for testing. Below is a photo and schematic. click the schematic for a bigger view. the scaling the forum adds makes some lines disappear.
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Thursday, September 9th 2010 - 6:22 PM

I get asked via email about build cost often, so I am adding a post about the topic.

When I started this project I set a goal to be able to build a laser cutter for less than $1000. Was I able to do it? I definately had less than $1000 invested by the time I was able to cut a shape with the laser under CNC control. I was not starting with an empty shelf though. I already had a lot of the cheap stuff like nuts, bolts, wire, terminal blocks. I also cut all my own parts on my router, some of it from scrap material. I used cheap surplus things like stepper motors, etc.

Since that time a lot of feature creap has raised the price. Non essencial things like a gas spring assisted cover, assist air pumps and high end stepper drivers raised the price a lot.

I have the BOM on line with realistic, if not weighted high, prices. It does not contain prices for the electronics or the tube. Each person is going to start with a different amount of parts and a want a different amount of optional items added. If you only have $1000 to spend and don't have some material and cannot make you own parts, I would not start the project. I would suggest $1200 is probably closer. Do the math yourself, before you start the project.

Note: Remember this is open source. Feel free to make things yourself from the drawings. I do not make any real money from selling my kits. Don't feel any obligation to buy from me. If you want to help the project, just donate to it.

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Friday, September 10th 2010 - 2:58 PM

eBay is a good place to start. LightObject.com also sells them. It is good to do some searching because there are always some hidden deals out there.

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Sunday, September 12th 2010 - 10:58 PM

I was messing around with the RepRap motherboard controlling the laser. Now the laser is not firing. I think I lost the common ground between the RepRap and the laser power supply. If I measure ground to ground on the scope, it jitters around between +/- 2-3V. This means the power supply enable pin was seeing in excess of 7-8volts. Something made a bit of a buzzing sound before it stopped working. I cannot fire it using the high or low enable.

Does anyone know the front end of the laser power supply before I tear it out?

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