Nozzles and blocks and hobbs, oh my!

Posted On: 2016-12-09 13:03:04 ; Read: 3048 time(s)

As a special Christmas treat this week we're bringing you a triple-whammy of stocking filler product releases! Get your digits fiddling with E3D's new hardened hobbs, plated copper heater blocks, and nozzles.

 

Note that we said plated copper, not copper plated! These blocks and nozzles are made of high temperature copper alloy and plated with non-stick nickel (and laser-engraved with the E3D logo for that bling-tastic finish).

 

Why Copper and Nickel?

 

Copper has more than three times the thermal conductivity of brass, and the copper alloy we have used is exceptionally temperature resistant, and will not start to soften or anneal until temperatures greater than 500°C, whereas aluminium begins to significantly soften above 350C. This makes it perfect for higher temperature projects where aluminium heater blocks simply can't cope.

 

The higher thermal conductivity will also slightly increase your heat-up times, and can make temperature control more precise.

 

Bare copper at high temperatures will react with atmospheric oxygen and begin to blacken, scale and flake. In order to prevent this we added a layer of nickel plating over all our copper components. This not only stops corrosion - the low surface energy of the nickel plating means that plastic tends to stick to it much less during printing. This means less gunk ruining the clean shiny finish.

 

These blocks really are very shiny.

 

Copper Nozzles

 

If you thought we had enough nozzles in our ecosystem then think again! Copper and nickel plating brings a range of advantages - particularly for advanced, high temperature applications.

 

Again, we're using the same high temperature copper alloy as our heater blocks which can easily cope with temperatures beyond 500C without annealing and softening. 

 

On the nozzle the nickel plating becomes particularly beneficial. Because of the reduced adhesion of plastic to nickel the nozzle stays cleaner, and gives exceptionally smooth top surface layers as well as clean accurate perimeters. The nozzles also stay clean and free of build-up.

 

Not only have we externally plated the nozzles but we've managed to get these nozzles plated with nickel  inside the orifice itself. This provides some hidden benefits -  resistance to material flow is reduced giving slightly improved extrusion response. The nickel plating also prevents degraded material adhering and building up on the internal walls of the nozzle.This is particularly beneficial with certain TPU based flexible materials which can experience degradation and build-up in some cases resulting in blockages after prolonged printing. Filled materials which are notoriously sticky also benefit here with improved flow and reliability, even with heavily loaded materials.

 

Getting up close and personal with a copper nozzle. You can see the silvery nickel plating all the way through, even in the final orifice.

 

Hardened Hobbs

 

We've got a full technical breakdown blog-post on these on its way, but we wanted to give you a quick overview in the meantime.

 

In short:

  • Hobbs do wear with abrasive materials.
  • If you only print casual amounts of abrasive materials you’re probably ok.
  • If you’re printing larger quantities, a hardened hobb solves the problem permanently.
  • We’ve developed hardened hobbs from the same ultra wear resistant material as our hardened nozzles, and they are a drop in replacement for Titan Extruders. You can get hold of them here!

 

After introducing hardened nozzles to cope with abrasive filaments we began to wonder if abrasives were also having an adverse effect on hobbs, causing them to wear more quickly.

 

This was confirmed by chance when we were working on another project, printing carbon-fibre nylon with Scaffold. After about a month of running abrasive materials regularly on the same machine we noticed that the carbon nylon extruder was starting to jam and grind the filament increasingly frequently.

 

Under a microscope we could see that some of the teeth were blunted, which is what led to the grinding and eventual jamming of the extruder.

 

 

One the left, a new steel hobb. On the right, a worn steel hobb.

 

As with our hardened nozzles we used a heat treated hardened steel to produce Titan hobbs with extreme wear resistance.

 

After extensive testing comparing the hardened hobb with a normal hobb, the results were clear.

 

The unhardened hobb had a similar amount of wear to the hobb we took out of the machine originally and we actually had difficulties getting it to complete the test.

 

By contrast the hardened hobb was essentially untouched apart from slight cosmetic wear of the black oxide coating, and it would appear that you are good to crack on indefinitely.

 

Even with extensive torture-testing, the hardened steel hobb shows only minor scuffing.


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