Upgrade Your 3D Printer With a Copper Heater Block

Hi,

Many 3D printers are fitted with Aluminum heater blocks. When attempting to print at higher speeds with a large ( 0.8 .. 1.2 mm ) nozzle, I ran into extrusion issues as the heater was unable to melt the filament at the required rate. Swapping out the heater for one with a higher power output resulted in some improvement but was still not satisfactory.

Further reading and research pointed to the thermal mass of the heater block and the thermal conductivity of the material as possible areas of improvement. Copper has greater density than Aluminum and much greater thermal conductivity. Despite a lower specific heat capacity , a heater block made of copper will store a greater amount of energy than one made of Aluminum. The higher conductivity will also ensure better heat transfer from the heater block into the melt zone of the nozzle. Rather than buy a readymade copper block I decided to try and make the block myself and created this instructable for anyone else who chooses to do so.

This block is sized to match the E3D Heater block that my printer uses but it should be easy enough to make one to fit your printer as long as the shape isn't too complicated and the threads for fasteners are standard sized and you can easily acquire a tap of that size and spec.

I Nickel plated the copper block using a simple method I found on Instructables. Nickel plating prevents slow corrosion of the copper and gives the part a nice appearance.

Copper Stock - 12mm x 25mm x 16mm or larger

Hacksaw Frame with an 18TPI blade / Bandsaw with metal cutting blade

Assorted Files

Silicon Carbide Wet & Dry Paper 150, 220, 320, 400, 600,800,1000,1200,1500,2000

Threading Taps - Typically M6 and M3

Tap Handle

Callipers

Steel Rule

Engineer's Square

Drill - Cordless , Electric hand drill / Drill Press

Vice

Countersink / hole chamfering bit

Centre Punch

Scribe ( for marking lines )

Begin by squaring out the raw stock by choosing a reference face and making cuts to roughly size the block. I would prefer to size the block on 2 sides and leave one side very long so the part can be easily held and handled. If the copper block seems hard to cut / file, you may be able to make it more workable by annealing it. Heating the block using a torch and letting it cool slowly will anneal and soften the metal.

Clamp the block in a vice and use a set of files to file a flat face on the block. Draw filing while checking regularly using a straight edge and a square will ensure a reasonably flat and square face. Repeat on 2 more faces to create 3 faces that are at 90 degrees to each other. If you managed to obtain copper stock that was already milled to the right size , you can skip these steps.

Use the calipers to mark out lines parallel to the 3 finished faces to dimension the block. Cut away the excess copper using the saw or by filing to the reference lines.

Use a 150 grit wet dry sandpaper, to begin finishing the faces to a flat and smooth finish. Gluing the paper down onto a surface plate, glass sheet or any reasonably flat surface is ideal. Use water with a drop of dishwashing soap to lubricate the paper and move the copper block over it with smooth strokes. Rotate the block by 90 degrees to sand all the faces.

Once you check the dimensions and the angles of all the faces, you can move to a finer grit of sandpaper.

I generally start with 150 grit and move up to 220, 320, 400, 600 and 800 grit papers.

I cut my heater blocks to size before I realized that handling such a small part was difficult. Make sure you don't make that mistake.

Mark the positions of the holes for the nozzle, thermistor and screw holes to secure the heater core and the thermistor cartridge. You need to be sure about the sizes of the holes and the details of the thread that needs to be cut in some of them. The holes, specially for the thermistor and the heater need to be as close to the specifications as possible. A loose hole will cause reduced thermal conductivity and poor performance.

Use the threading taps to thread holes for the Nozzle / Heatbreak and the screws to secure the heater and the thermistor. Ensure that the thread axis aligns with the hole axis perfectly. I used a spiral flute tap to cut the threads.

After the holes are tapped, use a chamfer / countersink bit to lightly deburr and chamfer the hole edges.

Use the bandsaw / Hacksaw to cut a slot to create a clamp for the heater. This is where I realized that having a large block of copper would make this easier to achieve. Since I'd already cut my blocks to size, I had to glue the block onto a piece of plywood to cut the slot. Copper heats up considerably when cutting on a bandsaw and that caused the glue to debond. Using a coolant and cutting slowly eventually worked for me.

Once you cut the slot, use a narrow file / folded sand paper to chamfer and deburr the cut edges.

Clean and degrease the block. Inspect it to be sure that there is no swarf or other debris in the holes.

Test fit the parts that go into the block. It may be useful to actually power up the heater and hold it at the correct temperature for a while. Handle this operation with extreme care as the block is loose and not secured to the printer. There is a serious risk of burn injuries if you are not careful.

If everything fits nicely, you can move to the next step. Should there be a problem in fitting the parts together, you may need to ream out the holes or rethread them as required. If the fit is loose, there isn't much that you can do and may need to start over.

Using the calipers / scribe, mark lines to indicate the edges of the chamfers on all the edges of the block. Clamp the block on a vice and use a fine toothed file to file the chamfers. You could use a jig to hold the block and file an accurate chamfer ( I'll post another instructable for that. Do check back in a week or 2 )

Once the chamfers are done, You can begin polishing the block. Polishing the block gives it a superb appearance and will also reduce the tendency for melted plastic to stick to it. Work your way from 1200 grit paper to 2000 grit. wet sanding carefully . You will have to polish the chamfered surfaces to the same extent.

If you plan to plate the copper with Nickel , you need not aim for a mirror finish on the block.

I Nickel plated the block using a plating solution of Nickel Acetate that I made using a Nickel strip and household vinegar. There is a good Instructable for this process on the website.