J-head lite v2
The reprap project used to mean something. There was a clear difference between people who rode the cutting edge and people who threw money at the problem. We learned that $20,000 3D printers worked just as well as $1,000 3D printers. We must now learn that $20 hot ends work just as well as $100 hot ends.
In the spirit of lowering the barrier to entry to 3D Printing, the JLV2 combines the holder of the J-Head, the heat sink of the Arcol, and the hot end of the MK7. We're pushing the envelope of design and thermodynamics to bring 3D printing mainstream.
Specifically designed for 1.75mm filament, This design extrudes PLA and ABS, as well as many other plastics. The extruder can heat up to 250C. It sports the Honeywell 100K ohm thermistor for accurate temperature readings. Unlike all metal hot ends, this design uses passive cooling. It does not require a fan.
PLA USERS: Have at it.
Made out of:
|1/2" PTFE rod||(McMaster-Carr # 8803K14)|
|PTFE wire sleeving||(McMaster-Carr # 5335K13)|
|PTFE barrel sleeving||(McMaster-Carr # 5335K18)|
|PTFE heat shrink tubing||(McMaster-Carr # 75665K56)|
|Laser cut oak mounting plate||(Lowes 1/4" Oak)|
|M6x1 stainless steal barrel||(McMaster-Carr # 90024A461)|
|Aluminum heater block||(Clinton Aluminum .3750X.5000 FLT 6061)|
|Vishay 6.8ohm resistor||(Digikey # RWMA-6.8CT-ND)|
|Honeywell 100k thermistor||(Digikey # 480-3135-ND)|
|Brass nozzle||(McMaster-Carr # 8952K33)|
|Ceramic insulation||(Mcmaster-Carr # 87575K85)|
|Heat Resistant Wiring||(skygeek.com # M22759/16-22-0)|
|Copper Heat Sink||(McMaster-Carr # 5520K44)|
Permatex anti-seize lubricant -optional
Heat sink compound -optional
Number 37 drill bit
10mm socket wrench bit, reamed to at least 6mm
All are available at your local hardware store or Radio Shack, except Kapton tape, which can be found from various online sources: Grainger, McMaster-Carr, Ebay, etc.
This process may take an hour or longer. These instructions are highly complicated. The risk of burning and/or electrocuting yourself is very high. Wear appropriate safety gloves while handling hot metal and live wires. I encourage novice users to not attempt this assembly.
Prep: Soak the heater block, the steel tube, and the nozzle in acetone or laquer thinner to remove residual cutting oil and/or particulates, which may jam the nozzle. -optional
1. Put some anti-seize lubricant on the nozzle threads and screw it into the block. Make sure it's tight.
2. Take the small PTFE tubing and cut it into 4 parts. Put it on the leads of the thermistor and resistor.
3. Coat the resistor with heat sink compound and insert the thermistor and resistor into the heater block.
4. Cut the "Tefzel" wire into 4 equal parts and strip them.
5. Solder the leads of the resistor and thermistor to the wires and insulate the joint with Kapton tape.
6. Wrap the block with the ceramic insulation and secure with Kapton tape.
7. Coat the middle of the steel barrel with heat sink compound.
8. Screw the brass nut onto the middle of the steel barrel.
9. Wrap both ends of the barrel with PTFE tape.
10. Put the heat sink onto the barrel.
11. Screw the barrel into the heater block.
Note: The end of the barrel that's countersunk is the top. Screw in the flat side.
12. Attach the wires of the hot end to your controller board.
13. Heat the hot end to 255C (smoke is normal).
14. Take a pair of vice grips and clamp it to the top of the barrel.
15. Take a wrench and screw the nozzle and the barrel together.
16. Take a 10mm socket wrench bit and tighten the brass nut down onto the heat sink.
17. Thread the PTFE holder onto the barrel hand tight.
18. Wait 2 minutes
Note: This part is delicate. It's very easy to strip the threads on the PTFE, because it's soft material.
19. Slowly tighten the PTFE holder onto the barrel hand tight. Do not over tighten. Do not under tighten.
20. Let cool.
21. Take a #37 drill bit and ream out the PTFE holder.
Note: I find it's best to use vice grips and clamp the drill bit to hand ream the hole. I'm looking for alternatives to this step, but that's the best I've got for know.
22. Insert the PTFE liner all the way down into the devie and trim the excess witha razor blade,
22. Take the wood mount and carefully insert it into the groove mount. The wood can break.
These PID settings are a good place to start:
define PID_INTEGRAL_DRIVE_MAX 10
define PID_PGAIN 2560
define PID_IGAIN 64
define PID_DGAIN 4096