3D Bot Shack
3D Bot Shack

Compact Extruder Build Instructions

These are instructions for building the single-hotend extruder.  The dual extruder is built similarly and requires twice the amount of parts (except it still requires just one dual extruder body.and only one set of parts for mounting to the x-carraige).

 

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Required Parts

Compact Extruder Parts

Here is a list of the parts required:

1 x M3 30mm Machine Screw

1 x M3 20mm Machine Screw

2 x M3 8mm Machine Screw

4 x M3 Washer

4 x M3 Nut

1 x M4 40mm Thumb Screw

2 x M4 Washer

1 x M4 Nut

1 x Extruder Spring

1 x M8 15mm Smooth Rod

1 x 608 Skate Bearing

1 x Drive Gear

1 42BYG Motor

1 Jhead Hotend

1 Extruder Body

1 Extruder Idler


Parts Needed for Vertical X-Carriage Attachment:

2 x M3 25mm Machine Screw

2 x M3 Nut

Printed Parts Supplied in Kit
These parts are included in the printed parts kit.

Step 1: Trim and Clean Parts

The first step is to trim any burs from the printed parts.  Ream out all holes to ensure correct fitting of M3 and M4 machine screws.  Check the filament path for any extra filmant from printing and clean it out if necessary.  Ensure the M8 smooth rod fits easily into the idler and clean/trim the idler as necessary.

Step 2: Remove Hinge Support
There is a "U" shaped support (see image to left) that is used to support the hinge part while the extruder body is being printed.  This support needs to be removed.  Using a razor blade knife remove this part and trim it smooth.
Here is what the extruder body should look like once the hinge support has been removed.
This is another angle showing the extruder body after the hinge support has been removed.

Step 3: Attach the Motor

Insert two 8mm M3 Machine Screws through the holes in the extruder body as shown in the image.  Now place the motor on the screws, followed by one M3 Washer on each screw, and finally one M3 Nut on each screw.
Here the motor has been mounted to the extruder body.
Step 4: Attach the Drive Gear
Place the drive gear on the motor shaft. Then insert a piece of filament into the filament hole.  Now line up the teeth/groove in the drive gear so the filament sits perfectly in the middle.  Then tighten the grub screws, securing the drive gear to the motor shaft.  Remove the filament piece.
Step 5: Assemble the Idler
The idler is built using the idler printed part, 608 Skate Bearing, and 15mm M8 Smooth Rod.
First, insert the smooth rod into the skate bearing.
Now push the bearing/rod pieces into the holder in the idler.
Side view of the idler assembly.
Step 6: Insert Hinge Nut in Idler

Take one M3 Nut and insert it into the nut-trap in the idler.  You can use a hair-dryer to lightly heat the nut to make inserting easier.  You can also plase the nut on the nut trap, then use a heated soldering iron to push the nut into place.  Both these techniques work pretty well.

Here the nut has been fully inserted into the nut-trap.
Step 7: Attach the Idler to the Extruder Body
You will now attach the idler to the extruder body using one 20mm M3 Machine Screw and two M3 Washers.
First, place a washer on the machine screw, then insert the machien screw through the hinge on the extruder body, then add another washer onto the machine screw.  Finally add the idler onto the machine screw and turn the screw into the nut that was previously inserted into the nut-trap.  Do not overtighten the screw.  You want it to be tight, but you also want the idler to move freely on the screw/hinge.
Here the idler has been attached to the extruder body.
Here is a side view of the attached idler.
Step 8: Attach the Idler Tensioner
The idler tensioner consists of one 40mm M4 Thumb Screw, two M4 Washers, one M4 Nut, and one short spring.
First insert the M4 nut into the nut-trap in the extruder body.  Now place a washer on the thumb screw, followed by the spring, then one more washer.  Now insert the thumb screw through the hole in the extruder body and tighten it slightly into the nut.
The tensioner is used to put pressure onto the filament to hold it tightly  against the drive gear.  To do this, compress the spring using the washer, then rotate the idler into place and rotate the screw into the slot on the idler.  Now tighten the thumb srcrew by hand to put the proper amount of tension on the filament.  You will learn from experience how much pressure to use, but basically you want a lot of pressure, but need to leave the spring not fully compressed.
Here is how the idler should look with the tensioner in place and filament inserted into the extruder.
Step 9: Attach the Hotend

You will use one 30mm M3 Machine Screw and one M3 Nut to attach the hotend to the extruder body.

First, insert the hotend from the side.  There is a tab in the hotend mount that first perfectly into the top slot of the jhead hotend.  Once the hotend has been fully seated, insert the machien screw through the holes, then tighten the nut onto the screw.  You want this tight enough so that the hotend does not wobble in the extruder.
Completed Extruder
Your extruder is now complete.  The image here shows two 25mm M3 Machine Screws inserted through the holes that are used to mount the extruder to a vertical x-carriage.