When buying cheap has its drawbacks and what you can do about it.

One of the major benefits of buying an affordable DIY printer kit is being able to easily replace any of the components. Due to the popularity of desktop FDM RepRap printers, the individual components that build up these kits are readily available and very cheap (assuming you are willing to wait 6 weeks for delivery). Ordering parts from the likes of eBay, Banggood or Gearbest can yield really great cost per units but there is a reason this is possible.

Mass production of these items in conjunction with bulk buying components and cheap labour is what leads to great savings being passed onto consumers. The downside of this means that costs can be cut by sending out items that wouldn’t necessarily pass quality assurance for some of the more high end manufacturers. Not all is lost though and with a little ingenuity you have a good chance to salvage items and top up their usability. Below is a few items I have had to do post processing on to make them usable including what to do and what you need to do it.

Heater Blocks

These simple blocks do their job perfectly, holding all the hot end components in their respective places. However, on a couple of occasions I have gone to use a new one and have hit a couple of snags. To fix the issues I found you will need the following:

  • M6 Tap and wrench
  • M6 HSS Drill Bit
  • Qty of M3 x 3mm grub screws

The first issue is a low quality thread that holds the nozzle and heat break. A good way to test for this is to try and pass a heat break completely through the threaded hole, you should be able to do this freely by hand with very little to no resistance. If you hit any snags, reverse the heat break out, fix the block in a vice and run the M6 tap right the way through clearing any flaws in the thread. As the tap passes through, you are highly likely to see swarf gathering around the tool as seen in the picture.

Although it may not seem like it’s making any significant modifications, these minor flaws can cause the heat break or nozzle to appear to reach its end when in reality it has just got stuck. This could also lead to greater torsion which is likely to cause breakages.

The second issue I have found is left over residue of aluminium caused by the rough drilling of the grub screw hole that secures the heater cartridge. This residue is still quite stiff, likely to be sharp, hangs from the M3 hole and dangles in the 6mm through hole preventing the heater cartridge to be installed correctly without causing unwanted damage. To rectify this, place the block in a vice and proceed to drill the hole using an M6 HSS bit gently so that it clears the residue.

Finally, and this doesn’t happen often so is more of a recommendation, replace the grub screw that comes with the aluminium block. There are high tensile M3 x 3mm grub screws available on eBay that are a suitable replacement. Although the grub screw doesn’t require a lot of force to hold the heater cartridge in place, I have found on 2 occasions now that the thread has been rounded and therefor unusable. This also renders the aluminium block unusable as you won’t be able to fix the heater and thermistor in place which is definitely something you don’t want falling out mid print.

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