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HSI Introduction & Tips

Time

Installation time varies by experience; typically this is between 15 to 45 minutes. The "Full HSI" build has significantly more inserts than the regular HSI build and requires additional time.

Additional Materials

  • Soldering iron
  • M3 heat set insert tip for soldering irons
  • Fine tweezers

Practice Block

If you are using inserts for the first time, print at least one practice block. Experience with inserts saves time and lowers the chances of printed part damage.

These blocks have holes in two orientations: flat and set at a 50 degree angle. The holes are identical in shape to those used in the case. Practice putting inserts in both types of holes until comfortable with the procedure.

Procedure

Setup

  1. Install the M3 insert tip on your soldering iron.
  2. Pre-heat the iron to a low temperature (200C is fine for both PLA and PETG).
  3. Allow enough time for your iron to heat up. A 40W iron may need two minutes.

Installation

Note

heat set insert These inserts have a rounded lip on one side. This end "sits" in the hole and maintains alignment with the hole during heating and insertion.

Tip

The insert holes have a slight inward slope. Resistance will gradually increase as the insert slides in place. Resistance greatly increases when the insert deviates from the hole.

Caution

Installing an insert leaves both the insert and surrounding plastic hot for several minutes.

Avoid touching areas of the case around an insert until it has cooled.

  1. Pre-set an insert into the hole using your fingers or needle-nosed pliers. It drop in until it reaches the first set of knurles (or pop in place with some pressure).
  2. Place the tip of the soldering iron on the insert. Do not apply pressure yet.
  3. As the insert heats, it will soften the plastic around it. Apply gentle pressure with the iron.
  4. Let the shape of the hole guide the insert.
  5. Once the insert is flush or slightly below the surface, remove the iron.
  6. Check if the insert is off-center by looking for gaps around the edges. The plastic should be evenly melted around the insert.
  7. If the insert needs adjustment, gently use fine tweezers or an M3 x 20mm screw to straighten it (while still hot). See below if the insert cools.

Fixing a Cooled Insert

Sometimes an off-center insert is not discovered until later. The most common symptom is a squealing noise when inserting screws. If this happens, back out the screw and try again; the screw may be threading at an angle. If this does not correct the issue, stop assembly to fix the insert.

Note

These instructions are still being fine-tuned.

  1. Preheat the soldering iron to a low temperature.
  2. Set the iron's tip on the insert, but do not press down.
  3. Allow three (3) to five (5) seconds for the insert to heat.
  4. Take an M3 x 20mm or longer machine screw and thread one (1) or two (2) turns into the insert.
  5. Use the screw to straighten the insert before the plastic cools around it.