Step 17: 2BEIGH3 3D Printer Hot-End

The 2BEIGH3 hot-end is designed for quick replacement or swap out from job to job.  Just 2 screws mount the device to the Z Axis board.  The Heater connects with standard electrical spade lugs and the thermocouple uses one of the support 6/32 threaded rods.  Because there are minor differences, you'll need to re-zero your Z Axis.

The 2BEIGH3 uses two tip types.
The first is the lower resolution tip.  This is a .023" mig welding tip. See http://www.thingiverse.com/thing:7814
The small aluminum block is tapped to 1/4 - 28....there we go....knew we'd use that  1/4 28!
The mig welding tip is drilled out with a 1/8" bit to about .200" from the tip.
The white cylinders are the Teflon/PTFE tubes we ordered.  One inside the other.

  Careful with ABS
While this hot end is designed for NYLON, it can have issues you need to watch for with ABS.
ABS changes states much faster than NYLON, and when you use ABS with this hot-end, you must not let the ABS idle in the hot end as it will tend to pool inside and the extruded material will start to vary in thickness/dia.  What this means is that you should always retract a few mm's of ABS or PLA material while preparing for the next print.
I typically have a 1/8" tube blowing cool air on the lower section of the white cylinder where it meets the aluminum to keep ABS from pooling.

High Resolution Nozzle
The second Hot-end nozzle is a higher resolution unit that you may already have in your tool drawer.  I have a free handful from a vendor as it had his LOGO on it.....A pocket oiler
It is made of aluminum
It is threaded
It has a 0.5mm ID that we can roll to a smaller ID
It's cheap
They're everywhere.  Even Amazon has ump-teen flavors.
(Of course you need one like in my photo, not an all plastic oiler)

Since I got my printer up and running, I have been printing parts for work and friends.....it's almost always printing or cutting!   The 2BEIGH3 can print a 55 degree undercut, but starts to drop threads after that.  So you have to design with restraints in mind.  More on that later.

1 each         1/2 OD x 1/4 " ID Teflon/PTFE Tube - each hot-end needs about 4"  MMC PN 8547K31
1 each         1/4" OD x 1/8" ID Teflon/PTFE Tube - each hot-end needs about 5"  MMC PN 8547K23
1 each         #8 washer
1 each         Coupler MMC PN 51215K106 or any HW Store
4'                   3/8 neopreme tubing (Plumbing Section of your HW Store) Cut to fit your installation.
1 each         #6/32  x 24" threaded rod
4 each           6/32 nuts
1 each           120 volt heater cartridge MM Carr PN 3618K119
1 each           aluminum block  Cut from MMC PN 6023K291 -
                       Multipurpose Anodized Aluminum (Alloy 6061) 3/8" Thick X 2" Width, 1' Length
1 each           0.023" mig welding tip - Harbor Freight  $10 for 5 pc's
2 each           male 1/4" spade terminals for #16 awg wire
1 each          ring terminal for the thermocouple
1 each           Delrin 1" x 1" x 4+ "   MM Carr PN 8739K92  each hot-end needs about 4"
1 each           1-2 amp 120 volt Light Dimmer
                       The Heater cartridge draws .56 Amps at 120 volts and a nominal 300ma at the printing temp
                        It is still not a light bulb, so we need a good Light Dimmer capable of 1+ amps.
                         The Heater cartridge is isolated  and CSA approved but you still need to use covered Spade terminals for Safety.
NOTE: As to PTFE or as the rest of us know it “Teflon Non-Stick Coating for cooking utensils” is of course the famous Dupont coating used by millions for cooking. As any inventor or designer wants those that duplicate his efforts to be safe, I’ll take a few lines to explain where concerns originate.
Since it’s invention back in 1938, there has been something known as the “Teflon Controversy”.  And to this day it is taught in colleges and universities.  A Google search on the term “Teflon Controversy” will provide you a wealth of insight.
As for an in-depth and scientific description of Teflon Non-Stick Coating for cooking utensils, this site is a good start.
As the author of this instructable and the designer of the 2BEIGH3, I am not a polymer specialist and can not speak for Teflon Non-Stick Coating or as some refer to it PTFE.
I can however, define the usage of Teflon in the actual 3D NYLON printing process.
1. While the heater cartridge can reach temperatures as noted 600F, this is not the actual printing temperature, as NYLON would boil at that value.
2. The actual temperature at print time is about 20 – 25 degrees above that of ABS.
3. The circular area of the Teflon Non-Stick Coating that comes in contact with heat is ½ inch”,  12mm dia. Or about 1/1000 of an
average frying pan.
4. The temperature at the point of contact on the hot-end is about 10 to 20 degrees higher than most people cook their meats but
certainly not as hot as an unattended frying pan left on the stove-top.
Again, this author respects and appreciates everyone's comments.

Cut/Saw and Drill the Delrin per the print
Cut and Drill the Aluminum per the print
NOTE: The ID of the larger tube is slightly smaller than the OD of the smaller tube.  After you have cut to length, place the larger tube in a vice or clamp and run a 1/4" drill through it's center.  We want a snug fit, so don't go larger than 1/4.  Otherwise hot plastic will find a way between the two tubes and as it expands a bit will start to limit the smooth flow of material to the aluminum block.
Chamfer the Top outside edge of the 1/2" tube so it's meets snug with the delrin.
Chamfer the bottom outside edge of the 1/4" tube so it'll sit guided into the top of the 1/4-28 hole.
    Note, this is where your plastic and NYLON will leak if there's not a good pressure seal.  The design is such that as you screw in the top connector, it will push the 1/4 PTFE rod down and apply pressure to the chamfered end.  This is not fixed, as the PTFE will expand the first time we heat it up.  If you notice leaking around the 1/2" tube and aluminum block, tighten the connector to apply more pressure to the inner tube.  The washer keeps the inner tube from sliding up into the connector.
You'll need to tap threads into the top of the Delrin block.  This is an "NPT" thread.  As Delrin is easy to Tap, and Tap's are expensive, you can do as I did.   Just take a old peice of 1/2" pipe and use your dremel to cut about 12-14 slots in the threads as shown.  Works great!  Again, time vs money.
Wrap three turns of Teflon tape around the threads of the mig tip.
You will need to drill with a 1/8" bit into the mig tip to about .2" from the tip
Use a sharp bit.
Use a very slow speed on your varible speed drill.  The metal is very soft.
Use oil...then use more oil.  10W 30 works great.
The drill process will push some of the metal out the tip.  Pull it out .
The 0.023 hole will still be clogged.
Use a 1/16 drill bit and just tap the bottom of the drilled hole....like you were going to complete the hole with a smaller bit.
DO NOT push something from the tip in.....Take a small wire and push from the inside (where you drilled) out and the shavings will come out the tip.  Use compressed air to blow out any other flecks of metal.  If it won't open up, tap it with the 1/16 bit again.

Crimp the Spade terminals to the heater cartridge wires.  Do not solder as at 320c, they'll come UN-soldered.
Screw the tip into the aluminum block - tight.  Be careful not to strip the tapped hole.  The goal is for the heater cartridge, to heat the alum and therefore the tip.  Measure and cut your threaded rod, install the thermocouple and you're good to go.

The threaded rods are in my photos slightly bent.  This is due to an earlier insulator design that wouldn't hold up to the mechanical stress.  And rather than cut new rods, I just bent these into position.

As to the light dimmer, it was to get us up and printing, but of course we'll want a more accurate way of maintaining temperature.
I suggest  using a standard industrial PID controller.  There are several on EBay for about $20.00 or so.
Below is a photo and wires labled so you can see how one is connected.  These always lack "how to" info.
This uses a "K" thermocouple.  It will come with a fancy plug, but cut it off and simply cross the two wires.  Where they cross the first point....that's where they sense.  This means you can twist the wire a few turns, but only the first "touch" is sensed.

<p>Been reading and rereading this tutorial and it looks doable although I feel it skips some explanations/steps here and there. At least for my total novice level.</p><p>The above aside, this machine seems to Work by moving the &quot;table&quot; around while a lot of other CNC/3printers I've looked at Works by moving the cnc part above the board around.<br>Is there any reasons for going either way, or is it just coincidal how this particular machine ended?</p><p>Anyone made this in the EU with metric Measurements, or maybe even found Places to easily buy the items needed?</p>
<p>Hey dintid, the instructable builds on </p><p><a href="http://www.instructables.com/id/Building-a-drawer-slide-CNC-machine-for-under-200/" rel="nofollow">http://www.instructables.com/id/Building-a-drawer-...</a></p><p>Helped me a lot, and I started out with very little knowledge, and no tools other than a mate's drill press(and the mate). Take it slow and buy the tools and components over time.</p><p>About the metric conversion, i spent a few hours at a big hardware store and found metric equivalents for everything. However, for the low-res table I chose 1/4&quot; threaded-rod for a bit more accuracy than 8mm, and a (tiny) bit more strength than 6mm. 6.35mm couplings are easy to get. Having said that, it's easier to find STRAIGHT 8mm threaded-rods than 1/4&quot; ones. Oh well.</p>
<p>Wow! Very nice, very professional. And, what is that CAD software you use to create the drawings, please?</p>
<p>First off, i can't make to make and hack this. one question though, did you seriously manage to build this for about $1000?! that is incredible. Also, is it truly capable of running the cnc router with an aluminum block?</p><p>Cheers to an incredible build!</p>
<p>I'm partway through and my cost so far including some tools is au$600. Estimate another au$200 by the time I've made the accurate cnc table, print table and print head. At current exchange rates that's about US$650 all up.</p>
<p>I can't believe this! I'm designing my own 3d printer/cnc mill and came up with the idea to use iron pipe as a low cost rigid framing material while installing a natural gas heater at my buddies dads house. I was 1&quot; off and was surprised how non pliable even 6 foot runs are, I had to move the heater! lol I googled iron pipe frame 3d printer and find my idea was already in use as a framing material. So cool! I'm building one with 24&quot; x 24&quot; x 24&quot; travel and also want to use a 400 watt liquid cooled spindle motor for some CNC mill/cutting/engraving action. Eventually I want to experiment with printing in carbon fiber by impregnating carbon fiber snippets 3 to 8mm long into both the hardener and resin then pumping them through a standard style mixing tube/extruder but designed in 2 halves made of highly polished stainless steel for easy cleanup. A laser cutting attachment would be nice as well but that is way down the road. Anyway, Great video, glad to see someone else had my pipe idea. Take care and keep experimenting. That's how progress is made... </p>
<p>any luck?</p>
<p>Can you use USB to lpt1 converter?</p>
<p>Canberra, Australia. Just starting out. </p><p>As I go I'll list the _metric_ BOM's</p><p>MOTORS: ebay - au$219 delivered: 4-axis ctlr/4nema23(283oz/in) steppers, PS &amp; parallel cable. Worried that these will be too powerful, but we shall see.</p><p>The only local who can supply the frame components is &quot;metalmart&quot; who will cut and thread but need a week's notice. </p><p>QTY; Desc; Thread<br>2;600mm pipe; m-m<br>3;300mm pipe; m-m<br>5;150mm pipe m-m<br>3;Elbow; f-f <br>1;Tee; f-f-f <br>3;Union; f-f - Unavailable - got 'sockets' which seem functionally equivalent.<br>2;End caps; f<br>1;Flange; f - could not get 4-bolt version, had to settle with 2-bolt.</p><p>frame: au$118:</p><p>metalmart minimum dia threaded rods are 10mm. Still looking but might just couple to the 6.35mm stepper shafts. Anyone think that's a bad idea?</p>
<p>u r my dick</p>
<p>Problem with my z-axis.</p><p>I have the nema 23 7.6kg.cm 6 wire from circuit specialists. 57BYG081</p><p>I'm using the Univelop tb6560</p><p>My wiring is A:R A-:G B:Y B-:B</p><p>About 15.5 volts and 12 Ohm across the pairs.</p><p>This is working well for x and y axis</p><p>I think that I burnt out the z motor because I'm getting R between pairs. I swapped out my 4 motor (for the extruder) but I'm not getting movement. I swapped for the spare driver board, but when I try to jog the z motor, I get a clacking noise and no movement.</p><p>I took the load off of my z-axis to make sure that it wasn't a power issue.</p><p>Is there a good way to isolate the problems. I think that my controller is okay. I swapped cables for y/z and the z-job moved the 'y' axis. When I connected the z driver/motor to the y controller cable I still got the clacking noise.</p>
<p>On the basic CNC table, I'm noticing a bit of flex in the y-axis. The lack of a rigid bracket and the wood extension from the y-plate seem to be limiting factors. I have backed off the velocity and acceleration of the y-motor to keep the movement smoother, but mounting the motors has been the most frustrating.</p><p>I notice that you mounted the X-axis directly to the pipe rather than to the aluminum brackets as the smaller source project did. Trying to bolt a plate tangent to the pipe and level was also a challenge.</p><p>Lining up the threaded rod with the motor shaft and the guide nuts fastened to the platform left me wishing that I had a way to make micro adjustments. I used some set screws to position the z-axis nut because I don't have tools precise enough to create that cut-out on the z-nut (At least until I get the CNC tuned).</p><p>This has been a great project, so thank you much for sharing it. </p>
<p>Hello Dear <br>Friend</p><p>I am <br>commercial expert of Atidam Co .</p><p>Our company <br>is in the field of Ostrich growing.</p><p>We are <br>going to do ostrich eggshell designing by a machinery system</p><p>Im looking <br>for a kind of engraving , carving and designing machinery for designing ostrich <br>eggs.</p><p>please help <br>me which kind of machinery can I use for this regard?</p><p>what is <br>your guid for this my demand?</p><p>please <br>send me your reply by email</p><p>Thank you</p><p>Elham Ghorbani</p><p>Email: <br>Italyleathers@yahoo.com</p><p>Websites: <a href="http://www.emu.ir" rel="nofollow">www.emu.ir</a></p>
<p>@taulman,</p><p>I am in the preliminary stages of planning my 2BEIGH3. I was curious if there is any more information on the new and improved Threaded Rod Nuts. In your update it says you have uploaded a dwg of them. I can not seem to find them. Any help would be appreciated.</p><p>Thank you,</p><p>Ryan</p>
<p>Thanks, thanks, THANKS !!!</p><p>I am wondering if I want to;</p><p>a) Go with the low precision table, then the higher precision, then the 3D printer in the standard size all on 1 inch pipe.</p><p>b) As above, but larger, perhaps MUCH larger on 1 1/4, 1 1/2 or even 2 inch pipe.</p><p>Are there any rules of thumb for this ? I suppose torsional stiffness &quot;matters&quot; somewhere along the line, but I'm thinking that MASS might also help a LOT.</p><p>c) Do the low precision, then the higher) precision tables, then do the 3D printer as a SEPARATE set of hardware, i.e. have both available at all times with no need to switch.</p><p>Part of my reasoning is that prints can take a long time, even a VERY LONG TIME and as an impatient fellow... I just might wanna MAKE something on a 2D table.</p><p>I know, more hardware takes more space and more money. This is probably something I should decide before I start, there are probably places to optimize for 2D CNC if I am not going forward with 3D printing on the same platform.</p><p>d) Fancy hardware; Are linear bearings THAT expensive ?</p><p>Are they worth it ?</p><p>================================</p><p>Thanks (yet) again.</p>
<p>I found linear bearings on amazon for $18 per 12 pack, which doesn't seem unreasonable (in the total scheme of things).</p><p>LM8UU - they seem to be packaged and marketed specifically for home built 3D printer projects.</p><p>http://www.amazon.com/Linear-Bearings-Printer-Mendel-reprap/dp/B00ED150S4</p>
<p>It's great!</p>
<p>Its superb<br><br></p>
Very creative. I'll build your system as soon as I have your design in <strong>Autodesk Inventor 2014 </strong>as a <strong>parametric model</strong>. Do you happen to have that? :-)
If anyone is having problems downloading the DXF files just right click on them, click save as and then add a &quot;.dxf&quot; at the end then press save.
If anyone is having problems downloading the DXF files just right click on them, click save as and then add a &quot;.dxf&quot; at the end then press save.
Ok, I have a question.... If the point of changing the XY table and drive methods is to exchange speed for torque, then aren't we making life way harder than it has to be? In my design, I can see a way to actually run both drive methods on the same table at the same time... well sorta. I could add a belt drive to both X and Y axis, which would be permanently connected. Then, give myself a way to disconnect the drive screw from the table and the X-carriage. It would then be run from the belt drives at high speed and low torque. The screw drives could be re-attached to run high-torque/low speed. The belt drives would not have to be disconnected at all. They would only have to have the power removed so the steppers can freewheel. The screwdrives would have no problem dragging the belt drives in tow, and I can't foresee any reason why it would hurt them as long as power was removed. <br> <br>Can your table be modified in this way? If it could, then, assuming you run dual parallel controllers, you could simplify the transition to inserting 2-4 bolts and the flip of a switch.
I too started with the same simple frame in mind with the intention of simply 'upscaling' it. However, mine morphed into something completely new and different. I also have the intention of switching back and forth between 3D printer and mill/router. I would also like to add the ability to do PCBs and laser. I didn't plan for mine to switch motion/axis to optimize motion for the different modes though.... bravo. I figured when mine didn't move on the X and Y fast enough, I would make some linear trucks for each, and switch to belt drive. I built it with that future upgrade in mind, and should be able to do it easily. Right now, I have a fried X stepper, and I'm awaiting the replacement..... <br> <br><div><a href="http://s1179.photobucket.com/user/thasatelliteguy/library/CNC%20Build%20as%20of%2011_3_2013" rel="nofollow"></a></div>
<a href="http://s1179.photobucket.com/user/thasatelliteguy/library/CNC%20Build%20as%20of%2011_3_2013?sort=3&page=1" rel="nofollow">http://s1179.photobucket.com/user/thasatelliteguy/library/CNC%20Build%20as%20of%2011_3_2013?sort=3&amp;page=1</a>
I dont understand why this hasnt been done. <br>Once you have you device with XYZ movement and a well thought out tool space, you can interchange any tool from router to engraver to extruder. <br>If your frame is rigid enough to handle router cutting a extruder will be nothing
Its brilliant
Very nice instructable! <br> <br>Do you have any 3d cad models of the whole assembly? It would be nice to bring up a .step file to better understand how it all fits together.
Looks kike an idea whose time has come: <br>http://www.kickstarter.com/projects/327919589/the-microfactory-a-machine-shop-in-a-box
very interesting..
I have been following your Instructible for about 3 months and have constructed a low res cnc to cut parts for the high res table.
Congratulations, M D A..! You'll be pleased to know you're in good company. There are about 80+ (that I know of) makers around the world building or using/hacking the design. I will mention, that once I had the lower res unit working that I ended up actually cutting more parts on it, than I did when the higher res unit was up. Again, congratulations as I, and a lot of others here know, it takes interest and study to make these units work!<br>taulman
It has been a while since I posted so I will give another update. Hopefully this info will help with anyone who is having difficulties like I am. Here is what I have found in the past few weeks. <br>Missed steps: I scoped the outputs of the parallel port and the input to the stepper board. There was no missed steps at all. In my parallel interface board, there is a HC244 level converter connected to the lines of the parallel port. This does the 3.3V to 5V conversion so the rest of the downstream electronics are getting full 5V. Since this was not the problem I had to do some more hunting and found the decay mode drastically affected my stepper motors when running at higher RPM. I was running at 50% decay but I changed it to 100% decay and my &quot;missed steps&quot; problem went away. I hope this proves useful to anyone facing a similar aggravating situation. <br> <br>Drive rods: I have been having frustrating problems with my threaded rod coming loose from the motor couplers or the couplers coming loose from the motor shaft. It is extremely annoying. Everytime I try to cut the thicker plastics, the rod decouples and I ruin my part. I tighten the set screws as tight as possible. I have already rounded out the hex keys on two or 3 of the set screw because I am tightening them so much and so tight. The lateral forces just seem to be way to high and are pulling things apart. I actually ordered some of the special CNC shaft couplers that are helically slit to help with misalignment issues. They help to smooth out the motion but the helix acts like a spring and creates a big dead zone when you reverse direction just like backlash but worse. They clamped around the shaft instead of set screws so they held much better but I had to remove them because of the dead zone. I am not sure what I am going to do about this. Until I can get this solved, I am dead in the water! <br> <br>Slides: These have been a major thorn in my side. I know the slides were not going to be very precise but the ones I have are ridiculous. I already mentioned on my first post about the use of a tension spring on the Z axis slide. Well I had to do the same on one of the X axis slides. I noticed when I reversed direction in the X axis, they would shift in the Y axis as well!!! The farther they were extended, the greater the shift. At near full extension the Y shift just by looking at it was 0.050&quot; or more!!! This was showing up on all of my test prints when there was an X axis direction change. I &quot;solved&quot; this problem just like the other. I put a tension spring from the end of the slid and attached it to the opposite slides aluminum U channel via a nylon zip tie. This created a nylon loop that would &quot;slide&quot; up and down the channel as the X axis moved and provided a constant force in the Y axis and greatly reduced if not eliminated the problem. <br> <br>Plastics: When I was purchasing my raw materials, I was having a hard time finding the 0.220 acrylic so I went with 6mm polycarbonate from Amazon. Since it is a harder plastic, it is also harder to mill. I have checked out online for some tips on cutting this stuff and everything I read indicates you need low rpm and high feed speed. Wellllll, this setup is just not rigid enough to handle those kind of forces and my motors top out at around 22 in/min which is waaaaay below the recommended feed speeds of anywhere from 50 - 90 in/min from what I have read. The bit also seems to catch alot and pull into the plastic or pull the plastic up. I have these same problems with acrylic too. I have tried milling thinner acrylic and polycarbonate and these really cause a lot of problems because they ride up the helix of the bit and cause the thin plastic to vibrate a lot in the Z axis and just make a mess with the edge. I am experimenting with trying to do a 2 pass cut of the 6mm polycarb. If my threaded rod will keep from coming apart this might be a viable solution. Higher feed speeds seem to cause a lot more slop in the X and Y axis so I have been trying to keep everything running at 150mm/min or less. <br> <br>Dremel: I have been dissatisfied with my generic dremel. I don't know if the name brand will be better but I am unwilling and unable to spend the cash to find out. I am convinced that a generic &quot;rotozip&quot; or compact router is a way better option to get more torque at lower rpms. Mine has stalled out too many times when I turn down the rpms to keep from melting the edges of the plastic. Plus you get a 1/4&quot; bit capacity and likely a much better collet system to hold the bit. Anything has to be better than the one I have. It is a Genesis rotary tool from Amazon. Works fine as a dremel but the supplied collets don't hold worth a darn when you have high pull-out forces. <br> <br>Well that is enough for now. I hope this helps anyone else that may be running into brick walls like I am. If anyone has any ideas please let me know. One of these days or months I will get this thing working!
Hi, rt, First, excellent detective work on the driver board and drivers. That is the single point of issues with all of the electronics I've seen. <br>Next, on the coupler, while I didn't have any issues, I talked to one user that bulit a larger unit and he user a zero backlash from MMCarr <br>Coupling Hub 1/4&quot; Bore, 3/4&quot; Outside <br>PN 9845T102 using a red Durometer spider <br>Next is the speed of the dremel....Seems I lucked out finding the right speed to cut acrylic with mine, but it eventually died from over use: ) <br>I bought a cutout saw (dremel like) from Harbor Frieght But it didn't have speed control like the dremel. Runs way to fast. <br>I found that there's a certain speed for each type acrylic, so I bought a autotransformer that allows me to change voltage/speed $50.00 <br>http://www.mpja.com/500VA-0-130VAC-Variable-Autotransformer/productinfo/15162%20TR/ <br>Works great. But it does take time to dial in the speed. Both RPM and cut speed. <br>I found that the 1/8 bit got hot so the plastic melted to easy. I got a blower nozzle for my air comp and put it on to cool off the cutting bit. That really helps. <br>mail me on my website and I'll see if I can find any other tips. <br>taulman <br> <br> <br>
Update 2: <br>Tried the different motors. They give about 3x linear feed as expected. After trying to cut some test parts, I think I am going to reverse my thoughts on missed steps. The output with the new motors is all over the map. I think the missed steps weren't as obvious with the slower rpm motors but the higher frequency signals for these new motors is making the missed steps much more obvious. Parallel port card here I come!
Hello again! <br>Here is an update to my previous post. I checked my parallel port and it is putting out 3.3V signals but I also scoped the steps and everything looks good. I scoped the step signal coming out of the parallel port and the clock input pin to the stepper controller and they have been identical on every scope capture. So I would have to say that I am not dropping steps. I was able to get my hands on some different stepper motors and I hooked them up to the signal generator feeding the stepper motor controller and they top out at 25kHz. I think I am going to try them to give a little more linear feed speed.
Hello,<br> I have been following your Instructible for about 3 months and have constructed a low res cnc to cut parts for the high res table.&nbsp; I had some questions at the bottom but I also wanted to share some of what I have learned.&nbsp; I have even contemplated making a parallel Instructable on using LCNC for this project.&nbsp; But that is for when I am farther along.&nbsp; Here is what I have:<br> <br> To save some money, I went the LinuxCNC route since it was free to try.&nbsp; Getting the motors to run with LCNC was not difficult.&nbsp; Since there is not a standard CAM module to convert DXF to gcode I had to try third party software.&nbsp; Try as I may, I could not get any software to reliably read in the DXF files from this instructable.&nbsp; I don&rsquo;t know why.&nbsp; Sooo, I went the long route and re-drew the parts for the precision table in Sketchup and exported the DXF from there.&nbsp; I have made some minor tweeks to the geometry of the parts but nothing drastic.&nbsp; Then I used a free CAM program (HeeksCNC) to create the gcode.&nbsp; Works pretty well.&nbsp; I do have to tweek the resulting gcode a little since LCNC gives some error messages during the import.&nbsp; The messages are actually useful and point you where you need to make some modifications.&nbsp; LCNC has an excellent gcode reference in their manual.<br> <br> Another difference is the CNC controller I am using.&nbsp; I got mine from http://www.sainsmart.com/new-4-axis-tb6560-cnc-stepper-motor-driver-controller-board-kit-57-two-phase-3a.html<br> This is good for 1/16 microstepping which is what I have it set to.&nbsp; I haven&rsquo;t noticed any odd behavior with this controller.&nbsp; I am going to verify my parallel port is giving 5VDC and scope the output to double check for missed steps but after cutting many test parts, I am pretty certain that it is behaving well.<br> I can control the motors well from the PC but they have a limited feed rate before they start &ldquo;misbehaving&rdquo;.&nbsp; I used a separate signal generator to feed TTL square waves to the controllers to find the top frequency I can supply the motors.&nbsp; My motors top out at about 8Khz with the above microstepping and 24VDC supply.&nbsp; That equates to about 2.5 rev/s or 1/8 in/s.&nbsp; Not very fast.&nbsp; Since your video is time lapsed, approximately how fast is your linear feed rate??&nbsp; After some research, I found a nice site (http://www.daycounter.com/Calculators/Stepper-Motor-Calculator.phtml) that had good calculations to determine the max rpm for a stepper motor based on inductance and supply voltage.&nbsp; It looks like I picked high inductance low amp motors (57BYGH207 motor from www.circuitspecialist.com) that limit my rpm .&nbsp; I saved a few bucks per motor but I am paying for it in speed.&nbsp; I thought I would pass that along in case anyone else had the same problem.&nbsp; Which motors did you get specifically??? Item 57BYGH104??<br> I am using a similar type end mill it is just half the length and consequently half the price.&nbsp; It is from amazon.com (http://www.amazon.com/gp/product/B003BIEUZY/ref=oh_details_o04_s01_i00?ie=UTF8&amp;psc=1).&nbsp; All the specs appear to be the same other than the length.<br> <br> My main reason for writing (other than...&nbsp; Great instructable!!) is I am having problems getting good output on cutting the parts (at least I think so).&nbsp; I have test cut many of the Ystrut pieces on various materials to get a feel for the output before making the final pieces.&nbsp; I have milled the profile in wood to a shallow depth and it looks nice and smooth but when I get to milling the plastic, the edge finish is rather coarse.&nbsp; I am experimenting using thin acrylic and the cutter seems to catch and grab the piece causing it to vibrate in the Z axis.&nbsp; The milling direction is such that the finish edge is conventional milling and not climb milling.&nbsp; I have experimented with different rpm on the cutter but I can only go so low before my generic dremel will stall out.&nbsp; I noticed that you show two different cutting tools attached to your Z axis.&nbsp; The first looks like a dremel type rotary tool and the other looks more like a roto-zip or small router which is shown in your video.&nbsp; Did you need to graduate up to a more powerful cutter??&nbsp; I am feeding about as fast as my motors will go (110mm/min).&nbsp; I just get bad vibration.&nbsp; Even going to thicker material the bit will tend to grab but the thicker material doesn&rsquo;t vibrate as much in the Z axis.&nbsp; I have even had the bit grab so much that it pulled it out of the collet during the milling.&nbsp; I replaced the factory collet with an acual dremel collet and that seemed to do the trick.&nbsp; The surface finish is still pretty coarse.&nbsp; I did find that the center drawer slide that I have on my Z axis has a lot of play in the Y axis.&nbsp; It can cause my cutter to &ldquo;sway&rdquo; in the Y axis by 1/8&rdquo; or more!&nbsp; Maybe I have a less than ideal slide.&nbsp; This was causing a LOT of coarseness in the Y axis cuts.&nbsp; As the table would move in the Y direction, the flex of the slide would act like a spring and cause jerky motion.&nbsp; I have been able to compensate for this by putting a tension spring on the end of the slide and connect it back to the Z axis pipe to provide a constant back pressure on the slide.&nbsp; I just wanted to get your feedback to see if you had any tricks you learned and didn&rsquo;t document in the Instructable.&nbsp; About what would you call reasonable tolerance on the output for the low res table??&nbsp; 0.012&rdquo;-0.015&rdquo;??&nbsp; Thanks for the help!
Looks like I will also have to remove my Step Signal Opto chip. I scaled up the skull and crossbones test file, included in Mach3, to .5 on first test cut. Things looked ok until I tried a larger 2.5 scale up of the same file. Looks like Y is missing steps, BADLY. The eyes of the skull and cross bones aren't straight. I may also bump up my voltage to 24v after I've removed and jumper the chip location. <br>

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Bio: is an Engineer with a background in electronics, optics, mechanical designs, chemistry, plastic injection molding and plastic die tooling.
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