Acrylic 3D Printer Filament Spool Holder - Laser Cut With Aluminum Mandrel

My first 3D printer kit came with a laser cut Acrylic filament spool holder that sported at threaded rod with nuts on the ends to hold the spool of filament. At first I didn't like it -- it didn't work all that well. Then I decided to replace the threaded rod with an aluminum bar that better fit the spool, and just like that it began to work perfectly.

Now that I've started working on a 2nd 3D printer, I needed another spool holder. After searching the usual places on the Internet, I was unable to find files for laser cutting a similar spool holder - so I did what any respectable maker would do - I made my own!

The end product is almost identical to the one that shipped with my first 3D printer kit, but doesn't have the words 3D Printer cut out of each side, and is designed to use SAE hardware instead of metric hardware. (Metric is harder to find and usually more expensive in the United States.)

Tools

To build this project you will need access to a CO2 Laser cutter capable of cutting 1/4" acrylic. If you elect to make the mandrel as I've described you will also need access to a metal lathe. Beyond this you'll need a screw driver and a set of center drills and drill bits (and normal lathe turning tools.)

My laser cutter is an (inexpensive Chinese made) 40 Watt CO2 laser cutter. It is small and can only cut about 8" by 10". To cut 1/4" acrylic it is necessary to make 3 passes - 2 at 4mm/second and one at 6mm/second.

Any sufficiently large metal lathe will do for making the mandrel. You will need the chuck to be able to hold and support a 2" aluminum bar about 3.5 to 3.75 inches long. If you don't have access to a lathe there are many other options. You could 3D print a mandrel. Or you could cast one with casting resin or epoxy. Or you could cut end-pieces from left-over acrylic (using the laser cutter or a drill with a circle cutter), etc. Be creative. :)

Materials

The holder base is made from 1/4" acrylic. Acrylic cuts well with the laser cutter. Your could also use 1/4" Baltic birch, or other materials with similar characteristics. If you are lucky enough to live near San Antonio, TX or if your city has a plastic supplier like Plastic Supply of San Antonio that sells the acrylic scraps left over from things that they make, you will be able to pick up scrap pieces for very little cost. Plastic Supply of San Antonio sells their scraps for $1.00/pound. That means that the acrylic portion of this project costs about $1.00.

The files I've designed for the base use 4, 3/4" long #6-32 bolts and nuts. Be sure to get bolts that are flat on the underside of the head such as the round head bolts I used. Cap screws will work too, as would truss head bolts. The ones I used came from Home Depot and cost $1.18 for a bag of 8.

The mandrel is made from a piece of 2" round, 6061-T6 aluminum bar. It is cut 3.625" long. Check to see if your city has a metal supplier. Here in San Antonio I bought my metal from Westbrook Metals. Whether you buy from Westbrook or from an online supplier such as SpeedyMetals.com or OnlineMetals.com, they will generally cut the item to the length needed. I used a metal cutting band saw to cut my bars. Chances are if you have a lathe you also have access to something you can use to cut your metals.

You will also need 5 inches or 3/8" round aluminum bar/rod. This is available at most hardware stores. I bought the piece I'm using from Home Depot, though it would have likely been less expensive to get if from Westbrook Metals.

The Files

The files needed to cut the acrylic base are attached to this step. They come in a few different flavors:

• FilamentSpoolHolderBottom.pwj5 - A LaserCAD file for the bottom piece
• FilamentSpoolHolderSide.pwj5 - A LaserCAD file for the side pieces, cut 2 of these
• SpoolHolder.dxf - A .dxf file with all pieces. Open this with Inkscape or another CAD tool to adjust as needed for your laser cutter if you are not using a lightobject.com DSP controller for your cutter.
• SpoolHolderBottom.dxf - Same thing, only just the bottom piece in .DXF (R14) format.
• SpoolHolder1Side.dxf - Same thing, only just the side piece in .DXF (R14) format. You need 2 of these.
• SpoolHolder.dc - A DeltaCAD file with all of the pieces

• 1st Pass: 4mm/second @ 72% power (68% minimum)
• 2nd Pass: 4mm/second @ 72% power (68% minimum)
• 3rd Pass: 6mm/second @ 72% power (68% minimum)

After cutting the pieces should look like those shown in the photos.

Assembly...

The photos tell it all... Simply insert a nut into each of the cut-outs in the base after fitting the bottom and side together. Run a 6-32 bolt (3/4" long) through the laser cut hole and into the nut in the bottom piece. Repeat for the remaining three bolt holes. The base is now assembled.

If you plan to make the aluminum mandrels that I use you will next cut the metal bars -- unless this was done for you when they were purchased.

Cut 1 piece of the 3/8" bar that is 5 inches long. In the photos you will notice that I made two mandrels, so there is two of everything.

Next cut 1 piece of the 2" diameter aluminum rod that is 3 and 5/8" (3.625") long. Don't worry about being exact. You may want to cut it 5.75" long. Some of the ends will come off during facing.

The 3/8" rod

The 3/8" rod will run through the center of the 2" diameter rod. We want it to fit loosely so that we have one more place where things can turn without adding any tension to the extruder of the 3D printer.

Face each of the small rods on both sides. Then add a slight chamfer to each end.

After this, use some sand paper to give the rod a fresh polish. Otherwise very lightly turn the rod - just enough to remove the oxidized layer.

Facing

Start by facing each side of the 2" diameter rod.

Turning

Next turn off a very small amount of material -- just enough that the whole piece is shinny and smooth and round.

Center Drill

After turning, use a center drill to start a pilot for the 3/8" hole that will run through the rod.

Drill

Then drill all the way through the rod with a 3/8" drill bit. Be sure to use cutting oil, plenty of it. Go slow. Nothing is worse than breaking a drill bit inside of a piece that you've put a lot of time into.

Chamfer

After the hole is drilled through, give the outside edge a light chamfer. You may also want to use a deburring tool to shape the 3/8" hole entry point just slightly.

Clean-up

Acetone nicely removes the remaining cutting oil and helps to rinse away turnings. I always follow this by a quick bath in water and dish washing liquid.

You can now insert the 3/8" rod into the center of the mandrel.

It should fit well on the holder.

Filament spools from Hatchbox as well as NinjaFlex and NinjaFlex-Semiflex fit this holder perfectly. Everything turns easily without friction. This one will be used with a large (600mm tall build area) Delta type 3D printer.

I hope many of you will find this spool holder useful! Thank you!