3d Printing, Making, Taz

How to build a Taz-5 3d printer, Part #9 – building the extruder carriage

Last time, I build the left and right assemblies for the X-axis of my printer. I finished the post saying that I’d look at the electronics and software in the next post – however I’m still waiting for some of the parts to arrive, and I wanted to carry on building and documenting it.

I decided to build the X-axis carriage and extruder – there are a lot of parts to print for this. I had some of these parts printed already because I’d created a extruder previously for a presentation at my work – so that’s why a few of these parts are in different colours.

Building the X-axis carriage

There were 5 parts that I needed to print for this (I’ve linked to the STLs for these parts):

single bearing

carriage mount

carriage supportlower carriage support

After printing out the main extruder support, I inserted two M3 knurled insert nuts into the side, which will allow me to attach the fan support later.

extruder carriage nuts

I also used a soldering iron to insert a bunch of M3 knurled insert nuts into the main X-carriage mount – I’ll use these to connect the other four parts to this mount.

carriage support

I inserted linear bearings into the double and single bearing mounts, and attached these to them to side of the piece shown above. I attached the extruder support to the other side. This allowed me to mount the piece onto the printer’s guide rails.

I also cut the guide rails down to size for the X-axis, so they weren’t protruding beyond the ends of the left and right assemblies.

x-carriage with cut down guide rails

Similarly for the Y-axis, I again cut the guide rails to size.

y-carriage with cut down rails

Adding cooling fans

There’s a couple of cooling fans on the X-axis extruder carriage. One of these can be printed from the plans on the Lulzbot site.

blower

I printed this out, and inserted four M3 knurled insert nuts to the the part so I could bolt on a 50mm computer fan.

hot end fan

The photo below shows this attached to the extruder mount using 2 M3 bolts.

extruder carriage with fan

The second fan is slightly more complex. Lulzbot shows a micro blower attached to their extruder assembly, which cools the Hexagon hot-end. However, this isn’t a 3d-printed part, and I’ve really struggled to find a micro blower (plenty of blowers which are 50mm, but none in the 20mm – 25mm range, which is what I need).

So I decided to solve the problem myself, using a regular 25mm computer fan. I used AutoDesk 123D to design a simple mount, which will direct the air flowing from the fan into a more directed stream. I’ve shown a couple of screenshots from Cura below – the one on the right shows the four mounting points where I can bolt the 25mm x 25mm fan.

When I printed this out, it was easy to bolt to the fan and then attach to the extruder carriage.

extruder carriage with carriage

I put this onto the carriage which I’d already installed – you can see how the printer looks right now in the photo below.

featured image

3d Printing, Making, Taz

Building a 3d printer – Taz-5, Part 8: Building the X-axis

Last time I attached the threaded rod and guide rails for the Z-axis. With these in place, I’m now able to start building the X-axis.

A few notes on this post before I begin:

  1. I ran out of black filament while building this part, so I had to use the yellow filament I’ve been using for my other project.
  2. This was one of the trickiest parts of the project so far. The X-axis involves a few pieces being bolted together, and I had issues with ABS parts shrinking slightly – which meant that holes corresponding to each other on different parts sometimes didn’t line up perfectly.
  3. Because I’m using a regular M8 threaded rod (rather than a very accurate ballscrew) I had to design my own part. I’ve uploaded the AutoDesk 123D files to my GitHub repository.

First things first – I’ll talk about the parts I could print out from existing STL files.

Thingiverse to the rescue

Lulzbot have kindly open-sourced the designs for all the 3d printed parts from the Taz – however, not all of the parts are 3d printed, which means it’s a bit more difficult to build the Taz from scratch. Fortunately, a Thingiverse community member has re-designed and open sourced the left and right parts of the X-axis mounts in a way suitable for 3d printing. They aren’t perfect matches of the Taz-5’s factory parts, which are made from acrylic. If the same 3d shape as the original was printed out, it probably would be too flexible for my machine to work.

The STL of motor mount end of the X-axis is available here.

x-motormount

The STL of the idler end of the X-axis is available here.

X-axis-idler-end

These are both really big parts – each of these parts took my Sintron Prusa i3 about 5 hours to print out. Fortunately they came out ok, with no delamination or noticeable shrinking.

Printing the double bearing holder

Each of the two X-axis ends have a double linear bearing mount – the STL for these is available here, and these fit onto the vertical guide rails. These printed vertically by default – obviously they could be printed in a flatter configuration, but I think printing vertically makes the part stronger, given that the linear bearings will be an interference fit (which means they are slightly larger than the printed part).

In order to attach these to the large end mounts, I used a soldering iron to insert 4 knurled M3 nuts into the mounting holes.

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I found that printing vertically did give me a slight problem with shrinkage. I found that the holes in the double bearing mount weren’t quite long enough to comfortably line up with the holes. However, it was possible with a bit of careful coaxing.

Redesigning the nut holder for the threaded rod

Each also has a mount to hold the nut for the threaded rod. The parts which have been open sourced by Lulzbot are designed for a ballscrew – and I’ve elected to use a simple M8 threaded rod. I re-designed this part to hold an M8 nut, with a cover which bolts onto this piece and traps the nut in place. I’ve uploaded the AutoDesk 123D designs to my Github repo here.

Using a soldering iron, I fitted 4 M3 knurled insert nuts into the back of the piece, and 3 M5 knurled insert nuts into the bottom of the piece.

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I then used 3 M5 nuts and washers to attach the cover to the piece, which encloses the M8 nut.

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I then used 4 M3 nuts to attach the piece to the end mount, through the 4 holes. Obviously the above steps have to be carried out for the left and right sides of the X-axis.

Attaching the parts to the X-axis guide rails

Now that I had two fully assembled parts of the X-axis, I was able to fit these to the existing frame. I had to remove the vertical threaded rod and the guide rails, and then re-insert them with the assembled X-axis end parts. This was a bit tricky – I had to thread the rod through the nut quite a way before it was able to fit into the coupler.

I threaded 2 x 10mm x 600mm guide rails through the holes in the side of the parts, which proved to me that the two parts were aligned well.

I am pretty sure I’m going to have to disassemble this again, so I didn’t tighten up any of the nuts or bolts (actually I’m 100% sure because I need to get the actual print head onto the horizontal guide rails).

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Attaching the Y-axis and X-axis motors

I decided to get all the motors attached, so I attached the motor for the Y-axis using 4 x M3 nuts (which I made early on in the construction process).

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And finally for this part, I used another 4 x M3 nuts to attach the left X-axis assembly to another stepper motor.

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This it for this part – next time I’m going to start ordering in the Arduino and RAMPS hardware to drive the motors, and test the movement of the X-axis in the vertical direction.

 

 

 

 

3d Printing, Making, Taz

Building a 3d printer – Taz-5, Part 7: Thread and guide rails for the Z-axis

It’s been a couple of weeks since I posted an update on this – I needed to get out to the garage to do some work on this and it’s been kind of cold so I’ve been avoiding going out there. But today was starting to warm up a bit so I decided to get out and do something.

The Taz-5 has a very precise threaded rod – called a ball screw rod – to allow the printer mechanism to run up and down the Z-axis. These are pretty expensive and take a long time to arrive from China (I can’t find them available anywhere else in the world), so I decided to try this with a regular M8 threaded rod which is cheaper and immediately available locally. I was able to buy some of this from Screwfix for under £10.

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I also needed to insert guide rails into the frame – I purchased some 10mm x 600mm steel rods from eBay for this.I fitted the rods into the frame of the printer so far, and used some electrical tape to mark where I needed to cut them.

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I used a regular hacksaw to cut these to size, filed the sharp edges down, and placed them back into the frame.

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I repeated this for both sides of the X/Z-axis frame, so I now have rails and threaded rod completed for one axis.

I decided to follow up on a few smaller things that needed to be done – one was to get a small “thumbscrew” to allow me to adjust when the Z-axis limit switch is triggered. The photos below show the thumbscrews I purchased from eBay, and where one of them fits into the frame so far.

Finally for this time, I needed to connect the stepper motor (which has a shaft of 5mm diameter) and the M8 rod (which is 8mm in diameter). Obviously there’s a difference in diameter, but fortunately there are custom connectors which are widely available, and are known as Flexible Shaft Couplers, or Beam Couplers. I purchased a couple of these, and inserted them into the frame as shown below.

These couplers can be very securely attached to the shafts of the stepper motor and the threaded rods using pre-fitted grub screws- however, I didn’t tighten the nuts in these couplers yet because I’ll need to remove the rods for the next step.

The photo below shows where I am in the project so far.

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Next time, I’ll start creating the X-axis which holds the printer unit.

3d Printing, Making, Taz

Building a 3d printer – Taz-5, Part 6: Connecting the X, Y and Z axes together

This will be a short post, but the printer is starting to actually look recognisably like a Taz-5 RepRap printer.

There’s not much left to do to connect the Y-axis and X/Z axes together. I needed to print out four identical pieces of the Y-mount chassis, and you can get the STLs for this part from here.

y-mount-chassis

When these were printed, I needed to insert a 5mm knurled insert nut into the hole in the main body of the part. You can see this in the photo below in the rightmost black part, whereas the other three parts hold M5 x 25mm bolts already.

y-mount-chassis

These parts are bolted into the aluminium extrusion rails at the bottom of the X/Z axes (which was constructed in the previous step) using 4 x M5 x 10mm bolts.

There were a couple of complications for me – these parts are designed by Lulzbot for use with 20mm x 20mm extrusion with a central groove suitable for M4 T-nuts, but my extrusion is slightly different – it has a groove used for M5 T-nuts. These are a bit bigger than the M4 version, and the tabs protruding from the base of the parts printed above clashed with the nuts – so I had to file these tabs off. This isn’t going to have any real impact on the printer, it was just a mild annoyance.

These parts slot into their corresponding parts on the Y-axis, as shown below, and can be bolted together:

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There’s not a lot of point in really tightening the bolts at this point – there’s going to be quite a bit of alignment required later.

Eventually the combined frames look like this.

x-y-z axes

Next time I’ll attach the threaded rods for the Z axis, and the guide rods for the Z-axis and the Y-axis.

3d Printing, Making, Taz

Building a 3d printer – Taz-5, Part 4: Constructing the X/Z Axis frame squares

This time, I’ll build the two squares that form the body of the printer’s frame.

For each of the two squares, I needed 4 lengths of 20mm x 20mm x 500mm aluminium extrusion. In the photo below, I’ve laid these out roughly in the configuration that they need to be assembled.

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There’s a few special instructions:

  • The two pieces on the left and right need to be tapped at the top-end for an M6 bolt.
  • Before assembling these pieces, you need to insert the M5 T-nuts for future assembly steps – so for each of the 4 pieces:
    • For the top and bottom aluminium pieces, put 2 T-nuts in the top groove and 4 in the front side;
    • For the left and right aluminium pieces, put 4 T-nuts in the front groove;

The corner pieces which attach each of these aluminium parts are not printed parts in the factory Taz-5. However, a community member has created STL files for equivalent parts and uploaded to Thingiverse. You can get the STL for this part here.

I printed out 8 of these parts (4 for each square), and each of the printed parts looks like the part in the photo below.

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It’s pretty straightforward to understand how to assemble the square – each of these corner pieces is bolted using an M5 x 10mm bolt to the four corners where the lengths of aluminium meet. It’s a bit tricky to make threat the bolts into the T-nuts. I found a carpenters set-square was useful to keep the aluminium pieces at right angles to each other while I was connecting them.

I’ve shown the first finished square below.

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And since I need two of these, I just repeated the steps described above.

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That’s it for this part – next time I’ll print out the parts which join both of these squares together, and attach them.

3d Printing, Taz

Building a 3d printer – Taz-5, Part 1: Y-axis, front end assembly

I really like my Sintron printer – but there’s a few things I’d like to improve:

  1. The Sintron wobbles quite a bit and I’d like a more rigid printer – this should allow me to print faster, and with fewer unwanted ripple artefacts on the Z-axis.
  2. The Sintron only allows me to extrude one filament at a time – I’d like a design that allows for dual extruders.
  3. The Sintron allows about a bed size with a maximum of about 200mm x 200mm (maybe a little bit more, but not much). I’d like to have a printer that’s big enough to allow me to upgrade the bed to a bigger size.

I’d also like the challenge of building a printer from scratch.

A printer that I’ve had my eye on for a while is the Taz 5 from Lulzbot. This is a pretty awesome looking printer and ticks all three of the boxes above. It’s commercially available, but the plans and any 3d printed parts are also open source. I’d like to see how feasible it is to order the individual parts and build this printer myself.

The other thing that I haven’t done previously is work with the open source Marlin 3d printer software – though I’d not expect to make any changes to this software beyond configuration.

I’m going to create a series of blog posts documenting the steps I take to build this printer, and you’ll be able to see my progress as I go along. I’ll use my Sintron to print all the necessary parts.

The last thing I’d say is that this is kind of a voyage of discovery for me too. I’m sure I’m going to make some/lots of mistakes along the way – I’ll try to document them so anyone following this guide doesn’t do the same.

Part 1 – Y-axis, front end assembly

You’ll need:

  • 2 of M5 knurled insert nut;
  • 2 of M3 knurled insert nut;
  • 4 of M3 x 25mm bolts;
  • 4 of M3 washers;
  • 4 of M3 nylon lock nuts;
  • 2 of M5 x 25mm bolts;
  • 2 of M5 washers;
  • 2 of 609 ball bearings;
  • 1 of M8 x 35mm bolt;
  • 2 of M8 washers;
  • 1 of M8 nylon lock nut;

The finished assembly for this part will look like this:

fully assembled front view

1. Download the STL files for the left and right assembly uprights, and print one copy of each – the links for these are below:

The STL for the Y-axis left corner mount is here.

The STL for the Y-axis right corner mount is here.

Y-axis left and right mounts

2. Now insert the M3 knurled insert nuts into the holes on top of these two parts. I did this using a soldering iron. I heated it to 400C, and placed the nut up on the hot tip of the iron. Then I carefully pushed the nut into the hole on top of each of the mounts printed earlier.

Y-axis left and right mounts - top view with nuts

3. Insert the M5 knurled insert nuts into the upper holes on the side of the mounts, using the same technique as described above.

Y-axis left and right mounts - back view with nuts

4. We’re now going to construct the bearing mount for the Y-axis. Print the bearing mount (you can download the STL from here).

Y-axis bearing mount

 

 

 

 

 

 

You can see with all of these printed parts that the edges which touched the printer bed are still quite rough from the brim (which I’ve removed). I have to sand each of these edges, and then rub some acetone around the sanded edges to smooth them off.

5. Next you’ll need to fix the 609 style ball bearings and washers into position using the M8 nut and bolt. The photo below shows how these are ordered.

Y-axis bearing mount - exploded view with bearing

Note that the washers go immediately beside the ball bearings, rather than on the outside of the plastic mount. The photo below shows this unit fully assembled, also with 4 M3 nyloc nuts inserted into the hexagonal mounts.

bearing mount

6. The front panel is not 3d printed in the factory Taz 5. Fortunately, a Lulzbot community member posted STL files for the front end with the bearing mount holes, and also for the back end with the motor mount holes. These aren’t symmetrical, so beward of this when printing them!

They are big parts – I had to lay them out diagonally on my Sintron’s heated bed, as shown in the screenshot from Cura below.Cura - y-axis front

I printed 3 of the front ends, and used an ABS/Acetone mix to weld the plastic parts together, as shown below. Again, this is still a bit rough around the edges, as I hadn’t sanded down the artefacts left over after peeling off the brim.

unsanded front panel

The photo below shows the part after cleaning it up with some sandpaper, and finishing with some 600 grit paper.

sanded front panel

Finally, I used a rag dipped in acetone to smooth out the edges further, as shown below.

acetone smoothed front panel

With hindsight, I think that printing only a couple of these pieces would have been necessary, rather than 3 pieces.

7. This is the final step, where all the parts are attached. First we attach the bearing mount using 4 M3 x  25mm bolts, which attach into the nyloc nuts in the bearing mount. Secondly, we attach the two left and right corner mounts using the M5 x 25mm bolts. The photo below shows the assembled front bearing mount.

fully assembled front view

The rear view of this part is shown below.

fully assembled rear view

Next time I’ll look at building the corresponding rear motor mount assembly.