Ryan's 1.0 Build

[r691175002]

Hey everyone!

I've been hoping to get a laser cutter for a while but the cost was prohibitive. I had always been considering building one myself; however, I didn't have the knowledge or confidence to start a build alone. After discovering buildlog.net, I decided to finally give it a go.

Planning was the first major step and took a few weeks. I read everything I could about the electronics and build. From there I cross referenced the bill of materials with the drawings and put together my own list. I printed out some of the more important drawings and made sure I understood every aspect of the machine. I live in Canada so messing up an order would cost time and money in shipping.

I ended up with a fairly precise list of stuff to buy (See an old version here: http://img209.imageshack.us/img209/584/partslist.png ). It is always a battle, but in the end I managed to fit some bells and whistles into 2600$ including shipping and a margin of safety (the first thing you learn about diy is it always costs more than you expect). I didn't expect to stick to the list 100% (and I didn't) but it is fairly close for the major components. If you are in the USA and have some self control you could fit this into 2000$.

I am doing the buildlog.net original open source laser but I will be making a few modifications which will be fairly obvious and are mostly cosmetic in nature.

I started by ordering only the mechanical parts, then the electrical (stepper drivers) parts and finally the laser. I didn't want to buy everything at once only to fail at the first step.
It was like christmas for a few days as everything arrived. By coincidence my buildlog.net, mcmaster and misumi orders all arrived on the same day in some 7 giant boxes. You can only imagine how happy I was for that perfect moment.


Anyways... Onto the build, I'm planning on doing a fairly comprehensive log so that it can also double as assembly instructions and hopefully encourage more people to attempt building a laser cutter.

The first order of business was cutting down on the parts scattered all over the floor. With thousands of screws, bearings, extrusions, acrylic pieces, etc laying around I really needed to start partitioning the parts off to keep things under control. The Z axis carriages seemed like a reasonable place to start since they could be set aside after assembly and are fairly simple.


Here is the Z-axis kit, plus my own allen keys. I was expecting to have to tap the pieces, but Bart had already done it


To get the bearings onto the screws I needed to apply some force. I slipped the rubber grips onto my vice and used a block of aluminium with hole drilled in it to force the bearings onto the screws.


Here is what the screws should look like, but check the drawings to be sure. It goes split-lock, washer, bearing, nut, washer, acrylic, washer, nut. You want 6 of these.


Three bearings a carriage, with a 4-40 screw in the side for adjustment. The hole has already been tapped so it just screws right in.
And done, nice and easy. Believe it or not almost the entire build is at this level of difficulty. Bart has already done all the hard parts by designing and cutting the parts for us!



Now I'm going to have to give up my secret. It pains me to give it up so soon but I really want an up-to-date image on the main page. I actually started this build a while ago. Nothing irks me more than following a build log that takes months to complete so this way I can keep things going at a nice pace. The following picture is about a week old but it is quite pretty so I'll use it as the official image.

Just remember, I may be about to do some really stupid things and mangle my build on camera. No matter how badly you want to warn me the mistakes have already been made.

[bdring]

That looks great. What is the skin material?

With regards to the screws fitting in the bearings. The screws are number #10-32 which are nominally 0.189" dia. the holes in the bearings are 0.187 dia. The suggested fix is to lightly sand the screws in drill or drill press. This is mentioned on the build instructions and on some of the drawings. I actually use a flat file and it takes about 5 seconds per screw. You method might put a little stress on the bearings. If you make sure the inner race is supported, which it looks like you did, they should be fine...but a lot more work

The new Delrin bearings are 5mm I.D. so a 5mm screw slides right in. Unfortunately they cannot be used on this design due to different v diameters.

[hoda0013]

Looks great!

[r691175002]

I pushed the bearings onto the screws for no particular reason, I just felt like sticking them in the vice. For any future builders sanding the screws sounds like an easier alternative.

The covering is expanded pvc. I tried to get dibond (one of the aluminium laminates) but a sheet was 100-200$ depending on the finish and they would have to special order it. I was personally hoping for black, but they had a sheet of red pvc (and only red) for 40$ on hand. They even cut it for free and the color has grown on me. I've got about half of the 8x4 sheet left, and unfortunately you aren't supposed to laser cut the stuff but for the price I'm not going to complain. I also slipped some 4.5mm acrylic into the lid in case you didn't notice the reflections. They cut the sheet for me and managed some pretty tight tolerances across all the parts so I was very impressed.

Here's some of the electronics I'll be using. Some of it has changed but it is still fairly accurate:

Motors are from Bart and I'll be using keling drivers. The kelings have adjustable microsteps which means that I can get the 1000 steps/inch for the retina controller. They are also a bit cheaper than the Gecko 4 axis controller.


Power will be provided by two cheap Chinese supplies off ebay. I had a 24V 3A supply already on hand, which I planned to convert to 5V. I don't know anything about electronics but I noticed that when I turned the potentiometer up I could go as low as 20V. My non-electrical background was telling me that if increased resistance lowers voltage, nothing has greater resistance than ripping the potentiometer off the board. The output dropped to 9V which was disappointing. I'll have to stick a regulator on the output.

The larger supply is 36V 7A. Bart suggested 24V but I want some extra kick if I ever move the stuff into a different machine. I also really need a 36V supply for another project so I may borrow it later on.


And finally some random parts. I feel like for a laser cutter to look truly complete there has to be some kind of fancy control panel. I'm not completely sure what I will display and what capabilities it will have but I promise that there will be a backlit display somewhere in this project. The laser pointer will be knife-edged with the CO2 beam.


After finishing the z-axis carriages it made sense to start with the v-rail. If I mess up the v-rail the entire project will come to a halt so I might as well get it over with fast. I started by marking lengths and cutting with a dremel.


There were two options here - bolt or glue. Bolting has the advantage of being tested and hard to permanently mess up. If I drill in the wrong spot I just don't use the hole. Gluing has the advantage of being fast and perhaps easy. You will quickly discover that when I work I tend to just go for it and clean up later. Drilling, tapping and aligning dozens of holes for the v-rail sounds like a drag so I just went with glue.


I am going to be completely honest, I did a flat out sloppy job of this. To begin with, I don't even know what kind of glue I used. I found a tube labeled only "goo" that said it was good for metal to metal in a drawer. Sloped some on the rail and slid the parts together.

No clamping at all, nothing to keep the pieces square. The shorter Z and Y rails turned out fine but the X rail was about half a millimeter wider at the edges. After the glue had half dried I discovered my mistake and jammed the thing in a vice to force the rails flush against the extrusion. Everything worked out and the rails slide flawlessly. I'd recommend using clamps but this is seriously hard to mess up.


I don't have the other carriages assembled at this point, but the Z slides wonderfully.

[bdring]

What are the details on the laser pointer? How is the quality of the spot? Where did you get it and what was the cost?

[r691175002]

What are the details on the laser pointer? How is the quality of the spot? Where did you get it and what was the cost?

It is an aixiz module ( http://aixiz.globat.com/ ) which is basically the same super cheap focusing assembly and 5mW diode that all the Chinese retailers sell. I picked up a truckload of them back in my diode laser days. You can swap out the diode so I have a bunch in varying power levels and colors but this one is hasn't been modified.

The spot is very good especially since its focusable. I'd recommend buying one from deal extreme for 4$ if you only need one: http://www.dealextreme.com/p/red-laser- ... m-5mw-5914

They also sell a cross module: http://www.dealextreme.com/p/red-laser- ... m-5mw-5942
I've got the cross as well and was thinking of throwing it on the x carriage but having two lasers for targeting might look silly.

[macona]

I have used those laser cross generator at work. The problem with them is the way they generate the veticle and horizontal lines is not central to the axis of the laser. If you want x mars the spot its best to use two line generators coming from two directions.

[r691175002]

If I end up using the cross generator it would be mostly for appearance so accuracy wouldn't be a huge deal.

I decided that assembling the rest of the acrylic parts would be a reasonable next step so here goes:


A few of the pieces need holes drilled in the edges. I did it the easy way with my mill/drill but if you are careful even a hand drill would be fine. I personally hate working acrylic since it always seems to make that nails on chalkboard sound and loves melting. You can use water/soap as cutting fluid but I didn't bother for drilling.

For the holes you need to tap just go slowly. If you've used a tap before there shouldn't be any problems, if in doubt go two turns in half a turn out and back the tap out if it starts to get filled with chips. As far as materials go acrylic is fairly easy to tap even if it makes horrible noises while you do it.


Here is the x-axis carriage. It uses a square nut instead of a tapped hole to save a little work. I didn't bother gluing the nut since it is held in place by the tightened screw.


Here are the y carriages. I'm almost 100% sure I have one of them backwards in this picture, just make sure you get the orientations right from the cad drawings.


The bearing pockets for the z-axis. Fairly straightforward although you need to tap a bunch of holes which sucks.


The bearings for the x and y axes. I consider this one of the weaker links in the build because the bearings are not 100% tight and hold the pulleys at an angle. I'll probably put some kind of spacer in there to take up the extra room. A properly sized washer should work.


And the motor mounts. Again, nothing all that special here. The gold bearings on the z-axis are mine. The kit doesn't come with enough bearings for both the tensioner and the 2 sets for the z-axis motor as they are not strictly necessary. I added mine in just because I had them around.

And that covers the acrylic parts. Nothing too challenging if you've tapped holes before. For most of these parts I just guessed which screws to use. In most cases only one will fit properly. The hardware kit comes with a few spares and since I glued the rails instead of bolting them there is a pile of extra screws. I haven't run into any problems.

[araknid01]

There's supposed to be a 5/16 split lock washer BETWEEN the two stacked bearings on the z-lift motor plate.

Build looks good though

[r691175002]

Thanks for the tip on the split lock washer, I've added it to my build.

Here is just a set of assembly photos for the frame. There isn't much to it, just make it look like the diagram and keep everything square:







I ordered 4 detachable hinges from misumi because they were the cheapest on the site. I only used two since the lid is coming off after the photo.

I deviated from the plans when it came to the lid, I wanted the entire lid to be transparent so I slid a sheet of acrylic into the slot. Because the inner surface was entirely acrylic I had to get creative with the joints and make sure it was strong enough to survive the two gas springs that would eventually support it.


This is a test fit of the sheet. I had the store cut it for me and they did a very accurate job of it. I siliconed the sheet in place to keep things simple. I did buy the rubber strip that misumi sells to hold sheets of acrylic in the slots but decided it would be easier without it.


Here is the hinge-side joint (on the bottom of the lid). Misumi sells screws that self-tap into the ends of the extrusions. I figured that one screw wouldn't be enough so I also used L-plates. The screw interferes with the acrylic sheet so I had to nip a corner off.


Here is the front joint. There are two screws going into the ends of the extrusions as well as an l-bracket.


The finished panel isn't as heavy as it looks and is fairly solid. There is a bit of flex in the extrusions but once its on hinges it shouldn't be a problem.

I was worried about the acrylic sagging so I let it dry upside-down. So far there hasn't been any sign of trouble.