One man's quest to remake the american manufacturing paradigm (or at least start a business).
Tuesday, December 14, 2010
That's just silly.
Now, while for the most part it fits together without hardware, the adjustable keyboard rack does require the drilling of the holes. After figuring out how to get poor 'ol CamBam (free version) to drill holes (and testing this), I started the program.
It started out ok, but then by the third hole it started generating a good deal of smoke. It took lots of experimenting with feed rates, pecking, and other such stuff to figure out what was going on: I was trying to drill holes with a downcut bit.
For the non-machinists out there, allow me to explain: your standard drill bit is what's called an upcut bit, that is the spiral flutes of the bit will bring chips up to the top of the bit. This is good for high-speed cutting, where you have to worry about keeping the bit clear. However, the drawback to using upcut bits in a CNC router is that it will cause the face of your material to chip and break near the cut, especially if you're working on a laminate material like plywood. For this reason I bought downcut bits, where the flutes of the bit spiral the other way. This eliminates chipping on the face, but has other drawbacks, such as not being good at drilling holes. What was happening to me is that the MDF dust created by the bit was being kept down in the hole where it was compressed and rubbed against itself a high speed, causing it to burn. To fix this, I changed the program so that I'd only drill shallow holes, the plan being to take the pieces over to the drill press and finish them after they were cut out.
Just before I was going to start cutting the actual pieces out, suddenly everything shut off. Turns out someone in the wood shop next to me blew a fuse. To avoid this in the future I used an extension cord to plug into a different outlet. I thought nothing of this at the time, but it would haunt me the rest of the night. After that I could not get the machine to do what I wanted. It wouldn't always move when it was told, and nothing I did or changed seemed to help. At 11pm I decided to call it a night and went home.
I came in this morning and after implementing a clamping system I thought up to keep the workpiece from moving (we thought that perhaps this was causing some of the error), I got back to work.
As one would imagine, the same problem was still there, but this time I noticed that it seemed to be limited to the Y and Z motors. I checked the connections, moved cords around to avoid possible interference (even though they were shielded), but no dice. The most annoying thing was that it would work fine until I actually went to run a program. A stroke of luck finally showed me what was going on: I turned the router on and had the program start and then when I saw it was moving I turned on the shop vac. I look back to see that the Y motor had stopped moving right when I had hit the vac's switch. Remember when I changed outlets? Turns out the new one didn't supply the same amount of current as the old one, so the motors weren't getting enough juice when the router and vac were on as well.
They're now on a different circuit. Off to cutting!
Saturday, December 11, 2010
It was a good day
First, the motors arrived right when UPS said they would. Installing one on the x axis went smoothly, but I ran into some problems once I started testing and tuning it. First, when I tried to run it it kept stopping at the same place on the table and clutching out. Turns out the set screw that was keeping one of the drive sprockets in place had loosened somewhat and was catching on the chain. For some reason it now wanted to be tighter than it had been before, which meant grinding a new flat into it's head to prevent further catching. Once that problem was solved I started the process of finding the right amount of current to drive the motor. Surprisingly, even with the current turned all the way up to 4.3A (the motor should only get 3A), it was still not able to move at the speeds I thought it should. In looking for a cause of this, I had the first of the day's breakthroughs.
It turns out the dip switches are "on" when they are in the down position. This meant two things: that the auto half current function (which helps keep motors from overheating) was off when I thought it was on, and that the boards were set to microstep at 25 subdivisions instead of just 5. While microstepping does give you much more precision (which I don't really need), it also severely reduces the amount of torque (which I do). I turn the auto half current function, set the driver to 2 subdivisions just to be on the safe side, modify the necessary settings in the software to reflect this, and resume testing.
The torque of the motor improves significantly, but it's still not performing as well as I'd expected. I could get it up to about 9 inches per second, but higher than that and it would choke, regardless of current. Now, when I was running my previous jobs, I had the machine running at feed rates of 50 and 100, so I was understandably concerned. I had no idea what was wrong, and was starting to get very frustrated.
Then it hit me: the units are different.
See, those feed rates of 50 and 100 were inches per minute, not second, so what I thought was a slow 9 was in fact 540 IPM, way faster than I'd ever need to go.
It's amazing how one small realization can improves one outlook on life.
After that, it was all cake. I re-tuned all three motors and cut the next prototype of the card dispenser. The y axis motor got a little on the warm side, so I had to let it rest half-way through the job, but I can turn the current down on that one with torque to spare.
There were some issues with the card dispenser job itself, but that was because of how I had it cut, not any hardware problems. I assembled it today, and it works quite well:
You can find other pics of it, along with screenshots of other things I've modeled in Solidworks that are destined to be milled out on a CNC here.
Monday, December 6, 2010
More shopping
*sigh*
Ah well, time to do some more CAD modeling. I'll have plenty to mill once it's up and running again.
Sunday, December 5, 2010
First prototype!
On Friday I milled out parts for a prototype business card dispenser. Check out the flickr set here.
Thursday, December 2, 2010
Two steps forward...
Yesterday, as you all saw, the machine was up and running. However, by the time I left it was once again non-functional. I'm pretty sure what happend was that the current was turned up to high on the z axis motor, causing it to overheat and eventually burn out. Usually I keep an eye on motor temp using an infrared thermometer, but it's batteries died. Thankfully my good friend Calvin had a small stepper I could borrow until I make sure the other motor is dead, or it gets fixed. I picked it up from him this morning, and that was one problem licked.
Another issue I had yesterday was that while the machine did work, it was painfully slow; that one part took around 45 minutes to mill out. This was because the router I was using could only spin at 500 RPMs, which meant I could only make the machine move at six inches per minute. I can't afford to spend that much time waiting, so I decided to bite the bullet and buy a bigger router. A wood working supply store near where I live happened to cary exactly what I needed: a replacement motor for a Porter Cable 3 1/4 hp router. Of course, about an hour after I bought it I get an email from my friend Jeff telling me that he has a mailer from that same store that's advertising a replacement router motor for $30 less than what I paid, plus a $25 gift certificate. I call the place back, and they told me that if I come back on Saturday (when that sale starts) with just the receipt, I can get the discount and the gift certificate. Two problems licked.
I get to the Asylum, rebuild the z gantry using the parts designed to hold the larger router, slap it back on the machine, wire in the new motor, install that, and start testing.
The new motor won't drive the gantry. Instead it just clutches out. No worries, the current is probably turned down too low, all I need to do is turn it back up until it has enough power. After much headache, I realize that the potentiometer on the driver board that is used to adjust the current is ever so slightly broken, so that the board doesn't work unless a slight pressure is applied to the dial. A small screw and some electrical tape later, and I've MacGuyvered it back to working condition. Third problem licked.
Now that it's all working again, I'm calling it a day. We'll see what happens tomorrow.
Wednesday, December 1, 2010
It Made a Thing!
My CNC made a thing!
It's a replacement for part of the vacuum attachment that was originally milled upside-down. As you can see here, the lobed part that hangs beneath the router has a channel that connects the two openings. That channel is supposed to face downwards, but if you flip the part the bolt holes don't line up. To fix this, I simply milled out another copy of the part and used the current piece as a guide for drilling the holes.
Much better!
Tuesday, November 30, 2010
It's Ready!
My CNC gantry router is finally ready to start making stuff! I'm sure I'll still do a lot of tweaking as I go along, but tomorrow I'll actually be able to start making things.
First order of business will be to go back to Atlantic Carbide to talk to their Onsrud rep, who apparently is only there between 6 am and 2 pm. I need to find out what the best bit for cutting masonite hardboard, which I plan to use in my first project: a business card dispenser. I've already done the CAD modeling and part layout; now all I need to do is to write the g-code. I should have a prototype to show off tomorrow!
I had to go and brag about it
Damn you, Murphy.
See, everything was ready. I had bought an extension hose for the shop vac, and onsrud cutters for the router. I had even done testing! Apparently, I hadn't done enough. Here's what happened:
I got the new motor wired up to one of my cables, poped it on the y axis (it had a longer drive shaft than my other motors, so it fit better there), connected everything, and loaded up the config wizard to make sure my settings were right. X and y axises still worked fine (so the new motor was good), but when I tried to test the z axis, nothing happened. I called someone over to listen to the motor while I tried to drive it, and apparently it would make a faint humming noise, but that was it. I disconnected it from the z axis lead screw, and it still didn't move. Out came the multi-meter. The cable was good. The port on the electronics box was good. I tested the motor on a different stepper driver board and it worked just fine, so it wasn't the motor. This leaves (as far as I know) only one thing that could be failing to work: the z axis stepper driver board.
Some good news: The guy who built the electronics is going to be here soon, he should be able to accurately diagnose the problem. With any luck, it's something silly I didn't know about, and he'll fix it. Also, I have an extra driver board that only needs very minor repairs to be fully functional, so even if the current z axis board is busted, we've got a replacement; no waiting for shipping.
Wish me luck!
Today it will be COMPLETE!!
It's about damn time.
Over the weekend I did some testing and tuning using only the x and y axises and a sharpie mounted in the router.
As you can see, with the first run (at the bottom), it started off pretty good, but as it progressed the x axis kept slipping. The problem was that since the set screw in the drive sprocket was so small (#8, no head), I couldn't really torque it down tight enough without stripping the socket and/or allen wrench. Thankfully my friend Calvin was around, and offered me a couple socket-headed screws that took a much larger allen wrench, allowing me to apply plenty of torque. While the larger heads did rub the chain, a little quick grinding with my dremel took care of that. As you can see, the final test showed no slippage at all.
Another mod I implemented at the suggestion of others was the addition of two brackets to help support the x axis drive shafts:
We had noticed that when the drive chains were tightened, it would cause the 1/4" drive shafts to flex. To counteract this, Jeff designed and milled out several pieces of MDF to hold an additional bearing for each drive shaft. This way, the shaft would be supported on either side of the drive sprocket, taking most of the lateral tension off the sprocket. They work great.
Off to finish the machine!
Wednesday, November 17, 2010
Setbacks and opportunities
This comment is becoming more prophetic than I'd like.
The machine has been capable of movement for a few days now, but the x axis has been troublesome. Even though it's being driven by a beefy NEMA34 motor that should be capable of over 600 oz-in of torque, I've been able to stop it with just a couple fingers. After sleeping on the problem Monday night, I decided to check the documentation of the motors and the driver boards, and discovered that the boards can only supply 4.3A of current, while the motor wants 5.5A. After consulting with some of my friends at the Asylum and some testing, we've decided that the best course of action is to order another smaller NEMA23 motor like the ones currently driving the Y and Z axises, which we know the driver boards can handle.
Some good news is that I had an interview with Because We Can for their internship position that went very well. However, I wouldn't be available until June, and they said that because of their size they can't reliably plan that far ahead. Still, I'm pretty optimistic about the opportunity, and will be staying in touch with them.
Monday, November 15, 2010
Completion is imminent!
The mechanics are all done, and the electronics are functional. All that's left is to finish up the wiring and software configuration, which I should be able to knock out today. After that's finished I'll do some test "cuts" using a sharpie in the router to make sure it's moving like it should, and then I'll start milling!
Other than some replacement parts and a few additional ones for the gantry, the first thing I plan on making is a toy I've been working on I'm calling the launcher. The original idea was a snow ball launcher, but then I realized that it could be used to launch pretty much anything than could fit down the barrel, so I made sure it could at least fit a tennis ball. It'll be large, unwieldy, and completely impractical, but it's a great example how a large CNC mill can be used to make things other than furniture and signage.
Wednesday, November 3, 2010
Getting Close Now!
As you can see, the machine is coming along nicely. I've attached the rails on the z and y gantries, which has allowed me to put all the main assemblies together. Jeff, one of the guys here at the Asylum, wanted to paint the torsion box with a stainless-steel paint, so it's all nice and shiny now. The next big steps will be to fasten the top to the torsion box (it's upside down now), and put it on top of the table structure. Once that's done, I can install the long x-axis rails and chains. Almost there!
Saturday, October 30, 2010
Busy Busy
On Tuesday I put in all the orders for hardware, and today the last package arrived! Sourcing the aluminum rails locally proved to be a great idea. It turns out that there's a local company called Admiral Metals that sold me full ten foot rails; this allowed me to avoid having a join in the long x-axis rails, which would most likely have caused a small bump. I also happend to run into a fellow CNC machinist while I was there who offered to help me machine any small parts I might need. I love this town.
I now have everything I need to finish the build; the only thing I have yet to get is an old computer to run the thing, but I've got several leads. Tomorrow is going to be a long work day.
Monday, October 25, 2010
Change in plans
Here's what happened: a few days ago I read on Because We Can's blog that they're offering a couple internships, one of which is focused on the use of CNC tech. As you can imagine, my first reaction was extreme interest, thinking I could do it right after I graduated, but after a few moments of consideration I decided that I'd probably be better off just going straight into business for myself.
A couple days later I found myself re-considering this internship. As it turns out, part of my resistance to it was the fact that I was very weary of becoming too interested in the bay area as a place to set up shop because I'm already in love with Boston. As I thought about this, I realized that this had caused me subconsciously to sabotage it's chances by only spending a month there, while giving Boston the better part of two. If instead I spent a full four months in Oakland, I'd be much more likely to get a more full picture of what living there was really like, and have more time to make the connections I would need. The more I thought about this idea, the more I liked it; even if I didn't get the internship it would still be a better plan. Another benefit would be that I would then be free to spend the full quarter here which, considering how long it's been taking to get the CNC up and running, would be very helpful.
After talking to several people about this plan and hearing no strong objections, and making sure my housemate wouldn't mind me staying an extra month, I decided to go ahead and put this plan into action. I'll miss not being able to see my father and step-mother for Thanksgiving, but being able to spend that much more time with them in the summer should make up for it.
Monday, October 18, 2010
Construction has begun!
The process of getting the gantry parts milled out, while complicated, is progressing nicely. When I went down to the SETC Thursday evening, there were indeed people there, and a shiny 4x8 ShopBot capable of doing all the cuts nicely. Unfortunately, the (one?) guy who can teach people how to use it was not there, and it was unclear when he might ever return to the SETC since he was currently in the middle of grad school. I did make some good contacts though, including one guy from a hackerspace near David Square called Sprout. I'm going to try to make it there sometime this week.
I also heard back from a guy I found through 100k garages who makes signs. His business is Village Sign Works, and it's run by a guy named Terry and his son. I drove up there Friday afternoon and spent some time discussing the job and generally talking shop. He seemed very eager to help me out. We couldn't get the g-code files I had from buildyourcnc.com to work with his system, so we decided that the best thing would be for me to take the DXFs I had, separate the cuts into layers based on depth of cut, and send those to him for an estimate. It's a good thing we did this, since an extra DXF I had also been sent turned out to contain several updated parts that I was strongly urged to use. I swapped out the old parts for the new, split everything into layers, and sent the revised DXF off to Terry. Hopefully I'll hear from him sometime today with an estimate and he'll be able to get cutting in the next day or so.
Thursday, October 14, 2010
CNC status update
A torsion box is a long thin box containing a grid of boards that form a ridged lattice. This will insure that the table to of the CNC mill will always be flat. Right now I've got most of the parts of the torsion box cut out; I just need help cutting the long sides of the box along with the top. Once that's done I'll assemble the box, build the table, and then start building the CNC onto it.
In the mean time I need to find a place that already has a CNC machine that will cut the out the parts for mine for me. Some other people at the Asylum tried to scope out a possible place called the South End Technology Center, but when they went during posted open hours on Saturday, the place was closed. Hopefully it'll be open today.
Tuesday, October 5, 2010
Much Progress!
- The Asylum guys saw no reason to make anything other than a full 4'x8' mill.
- One of them was already willing to buy the machine once I left town.
- Another said he knew of several places that would mill out parts the parts for us at cost.
This means that I'll get to build and have access to a full size CNC mill, not have to worry about getting it back to Cincinnati, and all it'll cost me in the end is my time and labor! This is better than I had dreamed of! Tonight we're meeting again to decide on a design to use, and possibly get started on the table that will hold the machine. Unless someone has found another well-tested design of the size we need, we'll probably be building this one.
In other news, this weekend I'm attending StrowlerCon, another Maker event of sorts where I have been assured I'll meet lots of awesome people.
Ye gods, I owe you people a report from D.C., don't I? I'd start a list of posts to do, but I'm afraid it would only encourage me to add to it rather than actually post.
Tuesday, September 28, 2010
Maker Faire Recap
The Maker Faire was amazing. All sorts of cool stuff from reps from big companies to small local shops selling their wares. Of course, I spent most of my time in the digital fabrication area. As you can imagine there were a great deal of 3D printers at the faire; most of them were MakerBot's cupcake CNC, including a few of the new version that just came out. At first blush, it doesn't seem that different, but I was told that it now supports microstepping, has a slightly larger print area, and of course comes with all the upgrades to the old cupcake. Honestly, I didn't see anything that really impressed me, but then again, I'm a miller, not a printer. I was more impressed by the RepRap Mendel, which has printing area of approximately 8x8x8, as opposed to the cupcake 4x4x6. Also, one guy told me it only cost him about $500 plus about 2.5 lbs. of printed parts, and was surprisingly easy to assemble (easier than a cupcake, he claimed). The Fab@Home guys showed off their versatility by printing in everything from silicon to cheesewiz using a variety of extruders, some of which were driven by air pressure. Neat idea.
I have to admit, after seeing so many printers, I caught the bug a bit and was tempted to get one myself. This lasted until Sunday, when I went to a talk given by a man from Shopbot Tools. His talk was largely about additive (3D printing) vs. subtractive (CNC milling) digital fabrication. Put simply, while there are some forms that can be 3D printed as one piece that can't be milled (hollow forms for example), milling is faster, cheaper, works on more practical materials, and can make parts much larger than even the most expensive printers.
Naturally I spent a lot of time talking to the guys from Shopbot Tools. They had three machines there: a 4x8 that was milling pieces for a construction set out of a full sheet of 3/4" ply, a 2x2 doing full 3D work to mill a pirate sign out of high-density foam, and smaller machine I didn't see running. I learned a lot by picking their brains, from the advantages of different types of cutters to pass depth increments to prices for electronic setups. It's too much to write out here, but I might make it a separate post later.
I spent some time checking out Alibre, an affordable CAD suite. Turns out it's designed to work much like Solidworks which I have come to know and love, but at around five grand I have dreaded buying. Alibre, on the other hand, is a lovely $99 for the basic version, and even if I bought the expert edition with the CAM suite add-on, it would still be cheaper.
I also went to a short talk given by the two owners of Because We Can on how to go pro as a Maker. Turns out what they're doing is similar in many ways to my own business idea in that their main tool is a large showboat CNC mill. I got a lot of good tips from them, which again I'll probably post about later.
Finally, there were all the other makers there. Most were doing jewelry, print work, or small soft goods; stuff that can easily be made by a couple people without any really expensive machinery or tools. One guy was selling messenger bags made out of bicycle tire tubes and scrap canvas from a sailboat factory. His company is called Vaya, and all their bags are hand-made by his wife. Cool stuff.
One last thing: While I was there I ran into an old acquaintance from Boston. Turns out he's also one of the directors for Artisan's Asylum, and can help me rent some space. Things are looking good.
Wednesday, September 22, 2010
The adventure has begun!
Saturday, August 28, 2010
The chair is done!
Saturday, August 21, 2010
IT'S ALIVE!!
Thursday, August 19, 2010
One way or another...
Tuesday, August 17, 2010
So.....Close......
Thursday, August 12, 2010
Boy, you'll be a burner soon.
Tuesday, August 10, 2010
Plans!
Sunday, August 8, 2010
Blogger, my old friend, we meet again
Tuesday, May 11, 2010
If you ever want to start anything, watch this. Now.
Sunday, March 21, 2010
New Solar Tech
Friday, March 19, 2010
Final Process Books
"Computer, is it the future yet?"
Tuesday, March 16, 2010
The Final Kitchen Crit
The final crit for my festival kitchen crit was today, and I have to say it was one of the best crits I've had at DAAP thus far. Our professor Tony brought in half a dozen local designers to critique our designs, and they had a lot of really valuable insights. Granted, it can be a little frustrating to get criticism from people who haven't been there for all the revisions and past crits, but it is a better measurement of how well you resolved the design. The main criticism I got for my design was that I didn't push things far enough, which I understand. I wasn't really trying to push the envelope with this project; I wanted something that would do a good job of filling the need I had seen simply and easily. Keep it simple, right? On the other hand, I've gotten a lot of positive feedback from the people I actually designed the kitchen for, so I'm pretty happy with my design.
Friday, March 12, 2010
Coop Confirmed!
Thursday, March 4, 2010
The Kettle is Finished!
Tuesday, February 16, 2010
Steampunk Kettle Project
Our next project in DesComm is to design some sort of tea kettle using some sort of theme as inspiration. Given that tea makes me think of Victorian England, the first thing that came to my mind was to make a steampunk kettle. Now, given that the steampunk aesthetic is known for very complicated and ornate artifacts, I'm a little worried that I'm biting off a little more than I can chew, but the idea is simply too cool to pass up.
Tuesday, February 9, 2010
Touch Everything!
Protoss Flash
So, since the snow has closed the entire university and I won't have the crit that was supposed to be this evening, I thought I'd post my work here. The assignment was to design a series of three flash drives with a particular brand in mind; I choose to base mine on the Protoss race from Blizzard's Starcraft franchise. Please let me know what you'd think; I've now have a couple more days to tweak it. Thanks!