Stepstruder MK6 Assembly 1.75mm

If you are upgrading a MakerBot Plastruder MK5 to a MakerBot Stepstruder MK6 using the MakerBot Stepstruder MK6 Upgrade Kit, proceed to the Stepstruder MK6 1.75mm Upgrade Instructions. Otherwise, continue below.

Tools You'll Need

flickr:4883011345

The Stepstruder MK6 goes together pretty easily, but you'll need a few tools to speed the process along:

  • Scissors
  • 1.5mm Hex Wrench
  • 2.5mm Hex Wrench
  • 13mm Wrench
  • Adjustable Wrench
  • Two Pliers
  • Soldering Iron
  • Sharp Knife
  • Tape

Strongly suggested

Parts You'll Need

Nuts and Bolts

flickr:5393438070

Custom Machined Parts

flickr:4902422996

MK6 Nozzle

flickr:5239088113

MK6 Thermal Core

flickr:4901836155

MK6 Thermal Barrier

flickr:4902422016

Laser-cut Parts

flickr:5430678983

High Torque NEMA17 Stepper Motor

flickr:5387990379

Hookup Wires

flickr:5426424922

Power Resistors

flickr:4883619302

Thermocouple

This is not included in the extruder box. The Thermocouple comes packed in a white wax paper envelope that is included in the Gen4 electronics kit, in the ziplock bag with the 6 pin heads and rainbow cables.

flickr:5471797277

PTFE Tubing

flickr:5187124827 (Large and Small)
flickr:5387780123 (Red)

Anti-sieze Paste, Heat Sink, Ceramic Tape

flickr:4883617164

Heat Shrink Tubing

flickr:5321072453

Part List

Prep Work

Peel off protective coverings.

The acrylic parts come with a protective paper film that covers the surface. Use your fingernail or a small screwdriver to remove this film.
flickr:4883010349

Filament Drive System

Add Plate A to stack.

Take Plate A and place it in front of you as shown in the picture.
flickr:5388392288

Add Plate B to stack.

Find Plate B and place it over Plate A as shown.
flickr:5390928453

Add Plate C to stack.

Plate C is two pieces of 2.3mm Black Delrin. Place plate C onto the stack as shown. Pay careful attention to the orientation of the parts.
flickr:5431686987

Add nuts to Plate C.

Add four nuts to Plate C as shown.
flickr:5431687479

Add Plate D to stack.

Plate D is the top of the sandwich. Place it on the stack as shown.
flickr:5432297582

Bolt stack together.

Insert M3x25 bolts

Insert four M3x25 bolts into the holes as shown. These are for securing the motor. In this step they help keep the layers aligned.

flickr:5432298014

Insert M3x22 bolts

Insert two M3x22 bolts as shown.

flickr:5432298460

Hand tighten nuts onto the M3x22 bolts. (Do not tighten nuts to M3x25 bolts.)

flickr:5431689131

Tape nuts on filament drive housing.

Place an M3 nut into each of the four holes and tape into place as show.
flickr:5431691621

Attach drive gear to motor shaft.

Bolt the gear onto the motor shaft as shown. The bottom of the drive gear should be 4.9 mm from the top of the motor. Use an M5 bolt to set the height of the drive gear as shown. Ensure the set screw contacts the flat part of the shaft.
flickr:5431644840

Fan mount assembly

Remove the fan connector

Using wire clippers clip off the fan connector as shown.
flickr:5432303188

Strip the wires

Strip the ends of the fan wires and the black/red cable.
flickr:5431693823

Add heat shrink

Place 1 inch of large heat shrink around both fan wires and 1 inch of small heat shrink around the black fan wire as shown.
flickr:5432304390

Solder wires

Ensure the heat shrink is a few inches from the cable ends. Solder the fan wires to 24 inches of black/red wire as shown.
flickr:5431695435

Shrink the heat shrink

Place the small heat shrink tube over the solder joint and heat as shown.
flickr:5432305568
Place the large heat shrink over both solder joints and heat as shown.
flickr:5431696645

Mount the fan to the bracket

Using two M3x16 bolts, two M3 nuts, and two M3 washers bolt the fan to the bracket as shown. Ensure the fan cable is oriented as shown. Ensure the fan label is facing the inside of the bracket.
flickr:5431697925

Bolt motor to filament drive housing.

Add the motor

Place the motor on a flat surface. Ensure the wires are to your left when facing the motor.
flickr:5431698531

Add the fan mount

Place the fan mount on the motor as shown.
flickr:5431699325

Add cork gasket

Place the cork gasket as shown.
flickr:5431699957

Add drive housing

Place the filament drive housing as shown.
flickr:5431689527

Tighten bolts

Tighten the bolts evenly. The cork gasket should be evenly compressed on all sides as shown.
flickr:5432300848
Tighten the bolts such that the drive gear is symmetric in the filament slot as shown.
flickr:5431038085

Pre-load all the t-slots with nuts.

By doing this before the assembly, you will save yourself countless trips to the floor to find dropped nuts, and other headaches. We use a simple three-step process:

1: Tape to "top" side of the acrylic

flickr:4883008381

2: Flip it, and insert nuts into the slots

flickr:4883612828

3: Tape over the nut

flickr:4883006853

Attach supports to one arch.

The supports are two of the same part. The tabs are asymmetrical though, so make sure the bottoms of the supports are flush with the bottoms of the tabs as shown. Tighten the bolts to finger tight for now.
flickr:4883602642

Attach other side to supports.

Take the other support and attach it on the back side. Tighten the bolts to finger tight only.
flickr:4882996509

Attach top to supports.

The top plate will bolt onto the arches as shown. Bolt it into plates and only finger tighten the bolts.
flickr:4883601102

Attach bottom to supports.

The bottom parts bolt onto the arches as shown. The hex nut cutouts are slightly off-center for mounting purposes. Make sure you keep them on the same side. You will also want to ensure that a line drawn through the hex cutouts will pass through the large circular cutout in the top plate. This is where the filament path goes, and we want it to be in-line with the mounting holes.
flickr:5388388192

M3x40 bolts into top piece.

These bolts are how the hot end is attached to the filament drive mechanism. Drop them into place as shown.
flickr:4883599498

1" spacers + nuts to bolts.

These spacers will ensure that the hot end is separated properly from the filament drive mechanism. Put one spacer on each bolt and then thread a nut onto it. Feel free to tighten the nut to 1/4 turn past finger tight.
flickr:4883598706

Attach filament drive to support.

The tabs on the filament drive ensure that you can only bolt the filament drive in the proper orientation. Insert it into the slots and then bolt it in place. Tighten the bolts to 1/4 turn past finger tight with the hex wrench. This is also a good time to tighten the rest of the bolts to 1/4 turn past finger tight as well.
flickr:5388583396

Superglue spacer feet to support.

Using superglue, or ideally acrylic cement, you'll want to attach the spacer feet to the bottom of the supports. Make sure the hole in the spacer lines up with the hex cutout or you'll be in for a grumpy surprise. If you're using superglue, its a good idea to scratch up the surfaces to be glued for better adhesion.
flickr:5387781167

Tape M5 nuts into spacer

Once the glue has dried, you'll want to insert the M5 nuts into the cutouts. Tape over these nuts to keep them from falling out during the rest of the assembly process and during usage.
flickr:4882990499

Hot End Assembly

Apply anti-sieze to threads.

If you ever plan on disassembling your hot end, it's imperative to apply the included anti-sieze compound to the threads. This stuff will protect against rust, corrosion, seizing, and galling that can happen at high temperatures. Simply smear a bit on your finger or a swab and apply it to the external threads. It should be applied to the nozzle threads and the thermal barrier tube threads.
flickr:4901833101

Bolt nozzle into thermal core.

To bolt the nozzle in all the way, get an adjustable wrench and your 13mm wrench. Screw the nozzle all the way into the thermal core by hand. Tighten them against each other with the wrenches. Use the 13mm wrench on the nozzle, and the adjustable wrench on the flat parts of the heater core.
flickr:4901831795

Thread in thermal barrier tube.

The thermal barrier tube is what provides the structural support for the PTFE as well as keeps the heat from travelling all the way up to the filament drive mechanism. Apply the anti-sieze and screw it all the way into the heater core. There isn't much to grip on, so just make sure you tighten it as much as possible with your fingers.
flickr:4902415866

Insert and trim the PTFE Tubing

Insert the small diameter PTFE tube into the larger PTFE tube as shown
flickr:5415897397
Insert the PTFE tube into the thermal barrier tube with the pointed end at the nozzle. Ensure the PTFE tube is pushed all the way into the nozzle.

If you're having trouble fitting the PTFE insert into the tube, put your PTFE barrel assembly into the freezer for 15 minutes or so. The PTFE will shrink and slip in easily.

flickr:5426056779
Using a razor knife trim the PTFE tube so that it's flush with the top of the thermal barrier tube as shown.
flickr:5426658652
PTFE tubing must be inserted all the way
This cutaway drawing shows the full insertion of the PTFE tube. Note that it extends all the way into the nozzle. You can check this by pulling it out and measuring it (should be roughly 80mm) or by unscrewing the nozzle with the PTFE tube in place.flickr:5238510988

Bolt on power resistors.

The power resistors are the heating element for the hot end and should read 5 Ohm (5Ω). Pay extra attention to the markings on this element as customers who have accidentally grabbed a similar but incorrect power resistor have had a hard time discovering this issue after properly wrapping their hotend. Additionally, those who have sourced their own inexpensive 5 Ohm 25watt power resistors have reported their power resistors exploding. Please do not experiment with those!

Use the provided tiny M2 bolts to attach them to either side of the thermal core. Tighten them down with the hex wrench.
flickr:4905441761

Connect Teflon Wires onto Power Resistors

Provided in the kit is a short length of PTFE insulated wire. This slippery bit of wire is capable of handling higher temperatures than your average bit of insulated wire. We'll be using it to wire the resistors together in a safe way.

First, cut the wire into two equal halves. The PTFE is rather difficult to strip with standard wire strippers, so get your sharp knife back out. Strip both ends of the wire, and insert it into its proper place as shown in the picture. Mark where the middle of the wire goes through one of the second resistor and then remove the PTFE covering the wire in that area.

The resistors themselves are 5 ohm resistors and we are going to wire them in parallel. The total resistance will be 2.5 ohms. This will be run at roughly 12v for a 57.6-watt heater. Since the new hot end has quite a bit more material to it, we need the higher heating capacity to make it operate. That is why you need a relay if you are using the Gen3 electronics.

Clip through both the legs of each resistor

flickr:5051771984
flickr:5051770856

Bend the clipped parts to the side a bit, so they will not get stuck on each other when closed.

flickr:5051149695

Bend the end of the Teflon-coated wire to form a loop.

flickr:5051148559

Place the loop in the end of the resistor.

flickr:5051147849

Squeeze the sides of the resistor leg to crimp them.

You will have to play with this a bit to get a solid mechanical hold. Repeat these steps for each connection. You can even add a bit of solder to the joints when you're done.

It is a good idea to use high-temperature,silver-bearing solder. The resistors will be getting up to at least 220°C, and probably higher. Normal leaded solder (64/40 or 63/37 tin/lead ratio) will become molten at this temperature (it melts at 183°C). We've used normal solder for a couple hundred hours, but it does get rather oxidized, and it's not ideal. If you use silver-bearing/ROHS solder it will have a higher melting point and last longer — 96.5% tin/3.5% silver melts at 221°C. You can also use plumbing solder that is 95% tin/5% antimony, which melts at 235°C. If you do, make sure to apply a small dab of non-acid paste flux, as plumbing solder often doesn't have rosin-core flux like electronics solder does. Its' not a major problem though; the worst that could happen is that you lose a connection and need to re-solder.

flickr:5051766188

When you're done, you can solder the same wire in two different places and have a much nicer connection.

flickr:4902410216

Cut the black and red wire into two 24 inch pieces

One piece is for the extruder heater, one for the motor.

Solder red/black wire onto PTFE wires.

From the PTFE wire, we can use standard red/black wire to handle the rest of the path to the MOSFET or the relay. Simply solder one of each wire to one of the PTFE wires.
flickr:4901822921

Insulate wires.

Starting January 1st, 2011, Stepstruder MK6 Kits will now include two sizes of heat shrink tubing. This will now be the preferred method for insulating soldered connections.

This photo shows the outer insulation, but make sure that you've also insulated your two solder joints from each other so they don't short together.

flickr:5319893013
flickr:5320493978
Other options include Kapton or electrical tape.
flickr:4901821953

Attach Thermocouple

Use the thermocouple included in your Extruder Controller v3.6 kit. This is the long, brownish wire with a metal tip on one end, and red/yellow wires on the other end. Attaching it to your hot end is very easy: we will be bolting it to the side of the MK6 thermal core.

First, wrap the tip of the thermocouple with a small piece of kapton tape to isolate it electrically.

Then, to attach it, take out your M2x5 bolt, and your M2 washer. Thread the bolt into the hole, and when you're about halfway down, put the metal end of the thermocouple between the washer and the heater core. Continue tightening the M2 bolt until the thermocouple is securely attached. You'll need to keep it in place as you tighten as it has a tendency to be pushed out before getting clamped down.

If the threaded hole is not quite deep enough for the M2 bolt, you can take an M3 nut and use it as an extra washer. This will give your bolt plenty of headroom.

flickr:5241443812

Insulate the thermal core.

The video below was intended for the MK5, but is relevant to the MK6 as well.

Prepare the ceramic tape

Cut one length of ceramic tape 70 mm long.

flickr:5241276232

Mark the center

flickr:5241275786

Use the thermal tube to press a hole in the ceramic tape.

flickr:5239252356

Your result should look like this

flickr:5240680343

Mark the center of the longer piece of ceramic tape

flickr:5240679701

Use the thermal tube to punch a hole through the longer piece.

flickr:5238656537

You now have two pieces that look like this.

flickr:5241274574

Slide the shorter strip around the thermal tube and under the wires on the sides with no resistors.
flickr:5241441548

Slide the longer strip around the thermal tube and under the wires on the sides with resistors.
flickr:5241441090

wrap it up with some tape.
flickr:5241523764

Pierce the insulation with a razor blade to reveal all four bolt holes.

flickr:5240986287

Clear the bolt holes of any insulation. Insert four bolts in the bolts holes to make sure they can all screw in.

flickr:5241581102

Place M3x22 into metal retainer plate.

Take the steel plate as shown and insert four M3x22mm bolts as shown. This will be the part that gets bolted to both the filament drive system and the thermal core.
flickr:4901821071

Thread nuts onto bolts.

Thread four nuts onto the M3 bolts as shown. These nuts will keep the retainer plate firmly attached to the M3 bolts when they get tightened down in a later step. Put them pretty close to the top of the retainer plate.
flickr:4901820187

Bolt retainer plate to thermal core.

Take the retainer plate and bolt the nuts into it using the provided hex wrench. Go ahead and tighten them down securely.
flickr:5241603118

Tighten nuts against retainer plate.

Securely attach the retainer plate by tightening the nuts against it. This will lock it in place and become the mounting point.
flickr:5240985359

Attach heat sink.

Provided in the kit is a circular heat sink. It is slightly oversized for the thermal barrier tube, so get your pliers and gently compress it a bit to reduce the diameter. Once you do that, it should have a nice friction fit over the thermal barrier tube. The heat sink is not strictly necessary, but it does help with keeping excess heat in the hot end and not the filament drive.
flickr:5240984511

Attach the hot end to acrylic assembly.

Attach the hot end to the filament drive system. The four bolts sticking down should fit into the corresponding holes on the metal retainer plate. The top of the thermal barrier tube should also fit into the hole in the bottom of the filament drive mechanism; sand or use a file to enlarge it if necessary. Pop it into place as shown.

Put some nuts on the end of the retaining bolts and tighten them down with the pliers.
flickr:5247431100

Route wires through appropriate slots.

On either side of the supports are some conveniently placed gaps that are perfect for routing wires though. We prefer to route the heater wires through one slot and the thermocouple/thermistor wires out the other slot. This will keep things tidy and also help you remember what is what.

flickr:5434377554

Tape on thermal cape under the motor

The thermal core can generate quite a bit of heat, so we've provided a thermal cape made from PET that should be taped on the back of the extruder as shown. This will prevent the vast majority of the heat from moving up and potentially overheating the motor.

NOTE: This part may be a silver color or clear; both work.
flickr:5247480942

Completed Stepstruder MK6, 1.75 mm filament configuration

flickr:5431692179

Next Step: Stepstruder MK6 Electronics Assembly

Unless otherwise stated, the content of this page is licensed under GNU Free Documentation License.