Wednesday, February 29, 2012

Part 5 Cont: Mounting the Arcol v3.0.1 Hot End: Section 2 of 2

I encountered a problem mounting arcol hotend on my standard clonedel carraige. There is an air gap between the hotend and cold end (wades extruder). This is an issue becuase as the filament goes through this gap it is no longer being guided and will miss the tiny hole on the arcol hotend.

To solve this the cool folks at lulzbot sold me a mount plate for their Budaschnozzle which is very similiar to the arcol hotend but shorter so you can get some more print height off your z-axis.

However even with the awesome mount plate I needed to modify if with my dremel so it would fit. What follows below are some pics I took to do this hack, dont judge ;)
I cramed some extra basla discs in before I put the mount on

You can see where I had to use my dremel to 'sand down' the plastic on the mount

Monday, October 10, 2011

Quality in Clonedel Parts

I was recently talking on IRC (with Kliment) regarding the advantages/disadvantages of Clonedel parts, and it turns out that a lot of work goes into making good molds that hold up and don't come out warped.

For instance, hex shaft on the Z-axis is needed to keep things level, the Clonedel's don't have this, I initially saw this as an advantage(and still kinda do until I start printing) because there had been preliminary reports of the top hex nut getting stuck in that shaft. Once I get the printer up and running I will find out how the Clonedel parts behave and they are any good (I think they will be OK).

In the meantime here is a blog entry from a German supplier called iFeel Beta of their gen2 Clonedel parts. They apparently worked very hard to get good quality parts cast. I recommend them as a source of Clonedel parts if you'r looking around and want to get started with a RepStrap.

2printbeta casted parts

Sunday, October 9, 2011

Part 5: Assembling the Arcol v3.0.1 Hot End: Section 1 of 2

So the after a lot of looking around at hot ends I found out about the Acol hot end and its numerous advantages, the one thing that was attractive to me was the print nozzel resolution of up to 0.35mm. That pretty much sealed the deal, so after a brief correspondence with Laszlo about certain things I ordered an un-assembled hot end, a hobbed bolt and two thermistors.

As of this writing, Laszlo's site is not 100% up to date on how to assemble the 3.0.1 version of his hotend, but but the basic idea is the same. It seems he swapped out the copper cap with an aluminum heat sink that I think he made with a lathe, and this version is using different types of insulators, other than that no big changes. For more detailed pics on the new hotend check out his Flickr stream.

The pictures and steps below should help illustrate how to put the latest version of this hotend together. I couldn't have done this without the great work Laszlo has done for the reprap community, his hotend is very versatile and mounts on other printers as well. LulzBot also has a variation of his hotend that they sell which is worth checking out if you want to buy something from inside the US, both are excellent hotends.

All the materials laid out

1. First twist the wires around the thermisotr and resistor, then slide a ferrule bootlace over it and crimp it shut. then trim off any excess wire.
2. Set the thermistor in the heatblock, apply firecememnt and then insert the thermistor into the middle hole on  the heater block gently without it touching any aluminum, I smeared some firecement in the hole first to get this affect. make sure you screw in the nozzle and protect it with paper so you don't accidentally seal it with firecement.

While the firecement is drying you can assemble the rest of the hotend, here is an overall picture of how the pieces fit together in stages.

3. Here is the first part of the hotend body assembled, pretty straight forward, I just used my hands but if you have a 2.5 hex you can use that instead.

4. The next part is a bit tricky, the white PTFE tube is inserted in the brown PEEK block until the ends are flush with each other.

Then the you can slide the aluminum heatsink over it and put it into the front end of the body.

5. This is basically the last part, you're going to slide on 4 of those laser cut slices and then screw them on, two m4 screws will also go in, this is for mounting to the extruder, you will have one wood piece left over for mounting when you are done.

Take note of the alumunim ring in the bottom laser cut disc, this will be on the bottom layer and is to assist the plastic as it slides into the PTFE tube.

6. Don't forget to wrap you peek blocks thread in PTFE tape (also know as teflon tape or plumbers tape here in the US). This will help seal the 

This image is courtesy of Laszlo! :-)
7. When your fire-cement is done drying (mine takes an hour, check your bottle) you are ready to screw teh nozzle onto the PEEK tube.

It is very important to make sure you have used PTFE tape on the PEEK tube and you tighten it as hard as you can against the nozzle because we don't want it to leak molten plastic :p

 slide the wire covers over the exposed wire, use some more heatshrink wrapping if some bare wire is still exposed. I was kinda lazy and just used zip ties to secure my wires instead of all the fancy wrapping Laszlo did, I'm not as experienced as him :p

If you wrapped your nozzle in kapton tape when the cement was drying you can just leave it on

Wiring the RIGHT WAY (Laszlo): Below are pictures to walk you through the steps needed to properly wire up your hotend, provided by Laszlo on his Flickr stream. I was in a hurry and decided to use zip ties but as Laszlo pointed out to me, wiring up the arcol the right way provides 3 distinct advantages:

  1. It protects the wires
  2. It provides wire relief
  3. Some heat crawls up the brown wire and this keeps most of it down near the heatsink
So learn form my mistake and try to do it this way instead, maybe when I test the resistor and heat up the hotend ill rewire it correctly and ditch the lameass zip ties ;)

Instead of soldering on a molex connector as Laszlo does in his guide, i just extended my cables with butt-splices and added terminal ends.
The thermisotr wires are very sensitive to being stripped so i used a bootlace to extend one of them as  I didn't want to strip those wires until they became bare ends...

The butt-splices after I used the heat gun from my rework station to seal the insulation

Soon I will be testing the heatend but that's after everything else is up and ready

Update: I added more firecement on the side to my resistor is completley covered, its not shown in this last picture, but its a good idea to do.

Part 2: I will remove that kapton tape and slowly heat up the resistor to 120C for 10 minutes, then 180C for 5 minutes, then 240C for another 5 minutes, after that the hot end will be done. Maybe ill rewire my hotend the way Laszlo say I should too....:p

Sunday, September 11, 2011

Z-Coupling Upgrade

Testing the z-axis revealed that the z-couplings have a bad habit of letting the motor shaft slip from them over time resulting in the threaded rod dropping from positions.

If I had a working printer handy I would have used Prusa Z-Coupling modification by Nophead but instead opted for the low cost lead-screw variant by Keegi since the hardware store was more accessible at this point.

Vinyl tubing and a coupling nut

I used a lock washer and hex nut to keep the coupling in place so it didn't unscrew itself from the threaded rod.

The lock washer between the two nuts keeps enough tension/friction so the coupling wont unscrew itself

Part 4: Z-Axis Build out

After mounting the smooth rods and measuring their placement with a plumb line I proceeded to mount the z-axis motors. However the slits for the m3 bolts were not positioned exactly where they needed to be, so some TLC from my dremel and 15 minutes later the motors were mounted successfully.
Drilled bigger holes with my dremel
 Once I worked up the courage to mount the X-axis on the smooth bars I had to be quick the epoxy before it dried up. About 10 stressful minutes later my hands were covered in hardened epoxy film but the x-axis was mounted successfully on the smooth bars

The epoxy did a great job of holding the bushings to the x-axis

Clonedel Spring Implementation
One of the cool things about the clonedel design is that there is no weird hex shaft for the hex nut and spring assembly to get stuck in.  Also it just looks cooler because you can see the springs compress as the x-axis moves.

Saturday, September 10, 2011

Part 3: X-Axis Assembly

I've been holding off on this part for some time because I was trying to order some replacement parts from Metrix Create Space regarding a piece that was poured rather thin from my eBay supplier and which I sort of repaired by using epoxy to glue it back together. The part in question is responsible for clamping down on the two X-axis smooth rods but was damaged during shipping (I think). This piece exists because with Clonedel's you cant really cast holes when you make a mold.

Regardless I pressed on and assembled the X-axis with success, well see how it holds up, a replacement will be printed post hast anyways...just in case.

x-axis assembly

The repaired piece upon closer inspection

I will say that an advantage to this Clonedel part over traditional printed parts is the absence of the shaft for the spring and hex nut thus resulting in no jamming with the spring and bolt.

Part 2: Y-Axis Build Out

After rejigging the frame, tightening everything up again after moving into my office, I was ready to actually make some real progress and install the y-axis.

After inserting an extra hex nut to accommodate for the "modified" (violently dremeled off) m3x25 bolt that was protruding too far into the pulley assembly area I was ready to get things moving.
Using aluminum pulleys which I love

With the help of my office-mate I was able to apply the epoxy and then evenly attach the bottom MDF plate to the newly modified Resin bushings with brass sleeves. Again with my colleagues help, he held down the T5 timing belt as I secured them with the m3x25 bolts securing the Y-Axis in place. 

Bottom view of Y-Axis
T5 Belts has good amount of tension on it but not too much

The Y-Axis moved evenly and without too much resistance.A gracious amout of WD-40 the results were only improved by two fold. I have heard of people using felt bearings instead and I think this might be the way to go next time.