Ultimaker rev.3 assembly: Extrusion head

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Assembly guide

Mechanical assembly of the Ultimaker revision 3 (click for an overview)

1. Frame

2. X-Y motors

3. X-Y axes

4. Extrusion head

5. Z-stage

6. Material feed mechanism

7. Mounting the electronics

Time needed:
About 60 to 90 minutes.

Tools needed:

Hex keys (2mm)
Hex key (1.5 mm)
Tweezers
Pliers
Small screwdriver (1.5 mm)

1 Step 4 - the EXTRUDER
2 What you'll need
- 2.1 Parts needed in this section
3 Assembling the housing
- 3.1 Parts needed in this step
4 Assembling the cooling fan
- 4.1 Parts needed in this section
5 Mounting the housing to the XY-frame
6 What you'll need
- 6.1 Parts needed in this section
7 Bowden cable / PFA tube
8 Questions or comments regarding this page? Let us and others know!

Step 4 - the EXTRUDER

What you'll need

**Parts needed in this section**
Qty.	Description	Notes
6	m3 nuts	2 used to mount for thermocouple, 4 used in the extrusion frame.
5	m3 bolts 10 mm	1 for the heating part, 4 used in the extrusion frame.
2	m3 bolts 30 mm	Used to mount the thermocouple.
2	wooden part named 8A	Not equal, at one part there are 2 holes a little bit milled.
4	wooden parts named 8B	No equal, but will fit in each other like a puzzle.
2	linear bearings	Metal tubes.
1	push in fitting	Tiny small plastic tube.
1	PFA tube	Transparent tube, one side taped blue.
1	horse shoe	iny blue U-shaped plastic that will stick later on the fitting.
1	m6 brass pipe*	*these pieces might be screwed together.
1	nozzle bolt*	*these pieces might be screwed together.
1	aluminium heater block*	*these pieces might be screwed together.
1	aluminium plate	with 4 holes.
1	peek insulator	with m6 screw-thread inside.
1	tiny piece of plumbing tape	needs to be used in between the peek and brass pipe.
1	heater	solid metal pipe with wires.
1	thermocouple	smaller solid metal pipe with wires.
1	thermocouple board	Tiny green board with electronics.
1	comb-shaped strain relief	tiny black plastic.
2	White plastic nuts	will fit the 2 30mm bolts. /small>
1	tiny transparant acrylic	should be mounted underneath the thermocouple board.
4	m3 studding	long bolts, +-95 mm with a black top part.
1	cooling fan	Used the assemble the cooling fan.
1	black polypropylene fan duct	Used the assemble the cooling fan.
2	m3 bolts 16 mm	Used the assemble the cooling fan.
4	m3 hex nuts	Used the assemble the cooling fan.
4	wooden parts named C	used for the tensioning of the belts.
2	6mm axis	sliders for the extrusion head.
4	30mm m3 bolts	used for mounting the housing of the XY frame.
4	m3 nuts	used for mounting the housing of the XY frame.

Assembling the housing

**Parts needed in this step**
Qty.	Description	Notes
6	m3 nuts	2 used to mount for thermocouple, 4 used in the extrusion frame.
5	m3 bolts 10 mm	1 for the heating part, 4 used in the extrusion frame.
2	m3 bolts 30 mm	Used to mount the thermocouple.
2	wooden part named 8A	Not equal, at one part there are 2 holes a little bit milled.
4	wooden parts named 8B	No equal, but will fit in each other like a puzzle.
2	linear bearings	Metal tubes.
1	push in fitting	Tiny small plastic tube.
1	PFA tube	Transparent tube, one side taped blue.
1	horse shoe	iny blue U-shaped plastic that will stick later on the fitting.
1	m6 brass pipe*	*these pieces might be screwed together.
1	nozzle bolt*	*these pieces might be screwed together.
1	aluminium heater block*	*these pieces might be screwed together.
1	aluminium plate	with 4 holes.
1	peek insulator	with m6 screw-thread inside.
1	tiny piece of plumbing tape	needs to be used in between the peek and brass pipe.
1	heater	solid metal pipe with wires.
1	thermocouple	smaller solid metal pipe with wires.
1	thermocouple board	Tiny green board with electronics.
1	comb-shaped strain relief	tiny black plastic.
2	White plastic nuts	will fit the 2 30mm bolts. /small>
1	tiny transparant acrylic	should be mounted underneath the thermocouple board.
4	m3 studding	long bolts, +-95 mm with a black top part.

1. Put four M3 nuts in the T/slots of the four sides of the box (don't fix them with the srews yet).

2. Take two sides of the box and place the linear bearings on the inside.
Please note that the four parts are not all equal!

3. Take the other two sides and push them around the linear bearings.

4.Take the bottom plate (part 8B) and push the two push-in fittings in the hole, which is deepened on one side.

5. Lay the plate with the push-in fitting on top of the aluminum plate, flat on the table

6. Take the tube (NOT the side where the blue scotch tape is!!!) and push it in the fitting till it hits the table.

7. The PFA tube should now protrude 8mm on the bottom side of part 8B. It should protrude 8mm exactly!!!!

PFA tube

IT IS CRITICAL THAT THE TUBE PROTRUDES 8MM ON THE BOTTOM. The reason for this is that the tube needs to be pushed on the brass pipe inside the PEEK. When the connection between the PEEK and the brass tube is not good, the material that is extruded will come between the tube and the brass pipe. It will solidify on that spot and clog your extruder! The only way to repair this is to remove the teflon tube from the PEEK part, and remove the excess plastic with pliers while the extruder is hot.

8. Push the tube backwards with your finger and put the "horse-shoe" around the fitting on the topside. The push-in fitting will now get a strong grip on the tube. After adding the horse shoe check whether the PFA tube still protrudes 8 mm exactly!

9. Now slide the tube with the blue scotch taped end through the box in the front right corner.

10. Push the box in part 8B.

11. Take the M6 brass pipe and the nozzle and bolt them together tight, but don't use excessive force! Make them as tight as you can by hand!
Mind that the small end of the M6 pipe should be on the inside of the nozzle.

12. Take the aluminum heater block and bolt it on the brass pipe.

13. Use a tool to tighten the aluminum block around the brass pipe, BUT DO IT VERY GENTLY. Don't use too much force, it will break the brass pipe!

14.Take the aluminum plate and push the PEEK in. This part insulates, so basically you need to call it PEEK insulator.

15. Now you can bolt the nozzle with aluminum heater block into the PEEK insulator.
To avoid plastic leaking the brass pipe use a tiny piece of plumbing tape (PTFE tape) to seal the pipe.
Make sure to wrap the plumbing tape around the brass tube 1,5 to 2 times.
You might have to cut the tape in half over its length, so there is no excessive material.

16. Check if the result looks like this, there should be NO GAP between the aluminium heater block and heater block.

17. Check if the end of the brass pipe is level with the edge inside the PEEK part. The PEEK part should touch the aluminum block, there should be NO GAP between them. If not, you have to tighten it just a little bit more, but again be gentle! If you use too much plumbing tape, chances are high it will not be level with the edge. Please take away the excessive plumbing tape and retry.

18. The next step is to slide in the heater.

19. Do the same for the Thermocouple.

20. Now take a 10mm screw and tighten it so the heater and the thermocouple cannot slide out of the aluminum heater block.

21. Guide the wires of the thermocouple and the heater through the diagonal opposite hole.

22. Guide the wires through the (wooden) box as well, on the same diagonal opposite side.

23. Now slide the box on top of the extruder part.

24. The Thermocouple board can now be mounted on part 8A. First take the comb-shaped strain relief and place two 30mm bolts in them.

Please note the orientation carefully! Use the two white plastic nuts (instead of the two black tubes as in the picture) and mount them on the bolts.

25. Slide the thermocouple board over the bolts.

26. The hole in the comb-shaped strain relief should now be above the two screws.

27.Take the acrylic part on place it on the bolts.

28. Place the thermocouple board assembly on top of part 8A, and bolt it tight on the bottom.

29. Take the thermocouple wires and fold them into the housing, to make things look tidy. Leave the end of the wires outside the box.

30. Slide plate 8A of the tube, guide the wires through the hole and place it on top of the box.

31. Take the four 10mm bolts and tighten the box together.

32. Take the M3 studding and bolt the top and the bottom of the box together, but don't tighten them yet.

33. When all four bolts in place, tighten them (only by hand!)

34. Check the corner where the PFA tube is placed. There should be a small gap (smaller than 1mm) between the wooden plate and the aluminum plate. The gap should not be bigger than in the picture. The gap means that the PFA tube is pressed well towards the brass tube inside the PEEK. If there is not a little gap, it can be that the PFA tube is not pressed well on the brass tube, which could cause leakage. If the gap is bigger, it can be ok, but make sure the aluminum plate is equidistance from the wooden plate. Otherwise the PFA tube is pushed towards the brass tube under an angle and will also start to leak.

Note that if you have short and long pieces of thread, that you use the long pieces on the opposite side of where you put the extruder hot end.

35. Mount the wires from the thermocouple into the thermocouple board. Red wire on the right, yellow wire on the left. Use a small screwdriver to tighten the screws.

If you ever decide to remove the nozzle from the brass tube after using the extruder, there will be plastic on the inside of the thread. This means that they're essentially glued together and cannot be removed when the nozzle is cold. Only remove the nozzle when it's HOT, otherwise you'll risk breaking it! (and be very careful if you attempt to do this

Assembling the cooling fan

**Parts needed in this section**
Qty.	Description	Notes
1	cooling fan	Used the assemble the cooling fan.
1	black polypropylene fan duct	Used the assemble the cooling fan.
2	m3 bolts 16 mm	Used the assemble the cooling fan.
4	m3 hex nuts	Used the assemble the cooling fan.

The fan will be 'off' by default, when turning on the machine.

1. Fold the Polypropyleen fan duct according the picture.

2. Take 2 16mm bolts and bolt the fan to the fanduct. Mind the orientation of the fan, the sticker on the fan should face towards the fanduct.

3. Check the picture for the orientation of the wires coming from the fan.

4. Place the fanduct on the bottom of the extruder head sticking out on the left side and bolt it together with 2 nuts on the studding.

5. Fold the fanduct together.

6. Guide the wire trhough the box. This might take some fiddling. A tweezer can be very useful.

7. When properly folded, the duct should not directly touch the extrusion nozzle or another hot element. Should you feel the need to modify the duct, ensure that airflow will not directly flow along the nozzle, since it really shouldn't be cooled too much (or you may have problems with extrusion later).

Congrats! You've just finished the most complex part of the machine!

The fan will be connected to the long black cable-assembly later (it shouldn't go onto the small circuit board).

Mounting the housing to the XY-frame

What you'll need

**Parts needed in this section**
Qty.	Description	Notes
4	wooden parts named C	used for the tensioning of the belts.
2	6mm axis	sliders for the extrusion head.
4	30mm m3 bolts	used for mounting the housing of the XY frame.
4	m3 nuts	used for mounting the housing of the XY frame.

The extruder can now be placed in the XY-frame.

1. Take one of the parts C with the bolts and place it into the LEFT bushing block, but don't tighten it yet.

2. Take one of the 6mm axes and place it from left to right in the extruder head, and make sure the front of the head is to the front of the machine.

3. Take the other 6mm axis and slide it from the front to the back through the extruder head. Keep the extruder head inside the machine, below the sliding blocks.

4. Now gently push the 6mm axis on the left in it's sliding block, while making sure the axes don't fall out of the head.

5. Now you can lift the axes gently into their sliding blocks.

6. Now you can place the remaining 3 part C's into their position

7. Finish them by putting the 30mm bolt in. DON'T tighten them yet. First clamp the 6mm axes. The clamps will also create more tension on the belts. It should not make a very high pitched sound, but it definitely should be audible, otherwise your belt is slack.Don't overdo it, be gentle!

8. Now tighten all the bolts in the sliding blocks.

9. Now the extruder is in place, but the X and Y axes need to be adjusted so they are square towards each other.

10. loosen ALL 8 tightening screws (only the ones that are on a long timing belt) of the pulleys then adjusted the squareness of the extruder axes and tighten the screws again.

Making sure can best be done by using part 3B and hold it between the sliding block and the frame.

Make sure the timing pulley does not move on the axis after the screw has been tightened. Clean the timing pulley if something is jamming the screw.

11. Do this on both sides of one axes, tighten the screws and do it for the other axe.

Do this properly, otherwise the mechanism will need too much force to move well.

12. When this is done, the bolts of the X and Y motors can be tightened.

13. First push the motor down, so the belt has a bit tension on it. Don't overdo it. Then tighten the bolts.

Finally the X and Y limit switches can be adjusted:
14. Slide the head all the way to one end and make sure you hear the click of the switch. If not, move the switch a little until it works. Then tighten the bolts. Do this for all four of them.

Bowden cable / PFA tube

A tube is used to guide the filament to the hot end. This mechanism is called a "Bowden Cable" (more information here). We use a PFA tube (not ordinary Teflon) for its great stability and operating characteristics. It is important that this cable is no longer than needed for the print head to move across the entire build surface.

On to the next section: