SD3 Extruder and Carriage Replacement

It took me a while to draw the E3D to scale, but I think I got it right.  This is based on the V6 of E3D. 

Here is what it would look like fully assembled (I didn't show the LM8UU bearings).

The part of the extruder that the motor attaches to is glued to the front bearing bock.  IN the picture below, I separated them so you can see where the glue joint is (yellow area).

I use something called Acrylic Cement from Tap Plastics which is a highly concentrated form of acetone.  Using this, glue joints are stronger than the surrounding material.  Once you have this, everything else goes together with screws, no more gluing. 

Other Assembly Notes:
The rear bearing block is held in place by a single screw, you don't want to overtightened it, you want it to be able "float", this way it doesn't bind during fast moves, it sort of "follows" along because it can pivot slightly.

Depending on how accurate your printer is, the holes for the LM8UU bearings might be a bit loose or tight, In my case they were near perfect, but after a little use the bearing started to partially come out after long prints, so I took them out, wrapped them in a couple of layers of Kapton, put them back, and they never came out since.

The Spring is something I bought at the hardware store.  I bought one of those bags of 100 springs for $4, and there were about 4 like springs that fit perfectly.  The "cups" the springs sit in, are 8mm diameter.  and the spring, uncompressed, is about 20mm long.

The little block the spring presses against can be adjusted slightly to apply more pressure on the spring.  Simply turn it counter clockwise a few degrees to compress the sring more, then tighten the screw.

The hole at the bottom (leading to the hot end is 4mm and it's designed to take a piece of PTFE tubing (4mm OD x 2mm ID).  At the top, in the spring loaded arm, the hole is actually a slot, and it's meant to stay open, this way it gives the filament a chance to move bit while it centers itself in the drive gear groove.

All the screw holes are for M3 screws.  I recommend using washers on all the screws.  The pressure bearing arm uses a M5 screw for the bearing.  Just reuse the bearing and screw from the original extruder.

That's about all I can think of for the moment.  Let me know if you have any problems.

PS.  I don't know where the temp zones are on the E3D, perhaps Elmoret can chime in.  So I'm not sure if the E3D will affect any of the surrounding areas.  Especially if you consider the E3D can be cranked up really high to print nylon.  Speaking of which I would like to get this printed in Nylon.

First of all, I forgot to add the picture I mentioned in the previous post.  I'll do that when I get home this evening. 

Second, to answer mdrVB6 question, the bump just on the front of the bearing block (where the horizontal platform screws in, is what hits the end stop on mine.  I'm currently using the Lawsy carriage replacements. 

I can also post the individual STL files (later this evening).   You can always use NetFabb Basic to separate all the pieces.

In fact it all started as a single model, then I imported it into NetFabb, where I separated the individual parts.  Then I imported all the parts into Repetier, rotated them and arranged them to create the current layout, then saved the whole thing as a single STL. 

You can always use NetFabb Basic to separate all the pieces.

Here are the remaining 2 parts:

I have printed the extruder mount front, back and bearing arm.  I did it in 0.2mm layers with 100% infill.  I can post some pics of those tonight.  I want to get the whole thing printed then do the full mod soon, just busy with work and life too. 

The bearing arm did not seem to have a perfectly flat surface across the back.  I would have rotated it that way to print a smaller overhang but then it would have needed supports, just like a slight raft for 1 layer under about half the part.  So I printed it with the holes closer to the bed. 

I am waiting on some connectors to come in for my extruder and heater wires, then I will install those on the wires so it can be easily removed and I will do this mod at the same time.  Hopefully by this time next week I will have it done.

I was able to get the rest of the parts printed this weekend.  I’m going to hit home depot tomorrow and see if they have the acrylic cement so I can get it glued together and also to look for a spring that will work.  My bearings also seem to fit just right.  I have not actually taken my E3D V6 off the printer to test fit it yet.  I’m not sure if you are looking for constructive feedback, but here goes:

•    Is there a reason you went to a single adjustment point on the X-carriage?  It uses a threaded screw like the stock carriage instead of double nut traps like Lawsy’s design.  I like to be able to adjust from both ends.

•    I think it could use some more material around the screw holes on the platform and bearing holders.  I’m only getting a single wall when I print the platform in 0.3 mm layers.  Also, the holes for screw heads are not big enough to hold the heads of the M3 screws I am using (identical to the stock socket cap M3 screws.  If I tried to get a nut in there, it would be way too small.

•    Is there anyway you can add the spring block as another stl, rotated to print correctly?  I had to print it on its side because, similar to the bearing arm, it doesn’t seem to have a perfectly flat bottom when you rotate it in repetier.  When printing like this, it seems to have a very then wall towards the edge and it did not come out very well.

•    I might consider adding a screw hole or flat edge on the x-carriage so it has a better surface to hit the X end stop with.  It doesn’t look like it was designed to hit the end stop and a screw here is another useful adjustment point.  I can send a pic if this is not clear.

•    The front bearing holder has a very thin edge where the extruder mount is supposed to get glued on.  I won’t know how strong it is until I try it, but it seems there is plenty of room to make this mating surface a lot bigger

Just a few more general questions: have you had a problem with your spring working itself loose and going flying off?  It seems like it could happen with all the extruder movement.  A small screw thru the bottom of the piece might stabilize it.

Thanks again for the design.  I’m looking forward to getting it up and running.  I really want a highly secure way to hold my hot end and this looks like it will do it.

A word to the wise regarding the pressure bearing arm.

You wanted to print the pressure arm in an upright position, so you won't have to use any supports.  While the rotated version I provided will let you print the part without supports, I'm not so sure it would be strong enough.

This part is designed to put pressure on the filament, and is always under compression.  Because of the way this part is layered, there is a chance that it can split along one of the layer lines.  So I would still try to print the part as it was originally oriented for strength.