PLA welding is a task that determines the joining of two different 3d prints or fixing cracks within the PLA 3d prints. Usually, PLA welding would require technical knowledge & other expertise which ultimately helps in fixing minor cracks and also contributes to the longevity of the 3d prints.
What is PLA?
PLA, alternatively known as Polylactic Acid is a renewable & popular 3d printing raw material with lesser resistance and strength. It is suitable for the beginner but not as harder as the PBT, PETG & ABS.
The followings are the PLA’s strength profile:
- Glass Transition Temperature – 60°C
- Heat Deflection Temperature At 455 kPa (66 psi) – 65°C
- Melting Onset (Solidus) – 160°C
- Stiffness to Weight: Axial, points – 1.6
- Flexural Modulus – 4.0 GPa
- Stiffness to Weight: Bending – 40 points
- Strength to Weight: Axial – 11 points
- Strength to Weight: Bending – 24 points
In all aspects, PLA seems to be fewer than PBT, ABS & PETG.
Why PLA Welding is Required?
Depending on the size and complexities, often we need to print parts separately and join them together. Also, due to the less durability, PLA needs welding to fix unusual cracks.
Or, sometimes large and complex 3d prints are not possible to complete on a turnkey basis & the 3d print users make prints separately and glue them together during the post-processing.
These are the situations when someone may need PLA welding:
- Adding the joints for stronger strength
- Spherical joints joint where gluing has limited scope
- Adding complicated shapes when gluing is almost impossible
- If there is any crack
- For ensuring a better joint that does not show up any gluing agent
Steps of PLA Welding
These are the steps you need to remember to weld PLA prints
- Keep the PLA parts in the power drill
- Align the filaments
- Ensure accurate speed
- Consider the angles & work accordingly
- Glue the gap with either a straight pattern or a rotating pattern
There are several different methods of joining PLA parts together.
Using a friction method, you can apply a power rotary tool to make necessary friction between the PLA parts. The friction creates heat and ultimately it melts down the edge of the PLA parts which are further joined together. Proper rotating speed will be very important here so that the entire edge heats evenly that ensure better durability. You should always have proper control over the rotary tool so that it doesn’t touch other areas which do not require to weld.
Heat Treatment Method
In case you do not have access to any rotary tool, you can use any metal tool to heat it up and then melt the PLA parts to join them together. You can place any screwdriver top on the flame and weld the PLA parts quite easily.
Be very careful while pressing the heated material on the PLA as it has a significant possibility to melt unusually.
A 3d Pen
A 3d pen can also help you in joining PLA parts together. A 3d pen usually uses PLA to draw visual 3d prints manually. You can just load some PLA and melt them where you would love to add. In case there is any extra material sticking on the prints, sanding or polishing during the post-processing would surely help.
Super glue works really well while joining inner parts together. Apart from creating a solid bond, gluing often helps in joining portions where welding may be impossible. Always use hand gloves while gluing as it sticks on the skin badly.
You can either weld the PLA parts in a straight line or in a circular motion. Depending on the seam and the depth, the pattern can be selected. for example, if the PLA parts are thick and wide, you can use a circular motion to join them for extra durability.
After PLA welding, you need to follow some post-processing techniques. For example,
- Sandpaper can help in removing the extra plastic from the edge
- Polishing can also remove the welding marks from the surface