The Longer LK4 PRO and LK5 PRO are both popular FDM 3D printers with similar designs. While the LK5 PRO offers a larger printing area and several hardware improvements, LK4 PRO users can also upgrade their machines with some practical modifications.

This guide introduces several upgrades that can help improve the LK4 PRO structure and make it closer to the LK5 PRO experience, including cable protection, cooling safety, spool placement, and print surface improvements.

1. Install a Hotbed Cable Bracket Holder

The LK4 PRO has a Hotbed power cord simply connected via a clip-on connector. This, as a result of repeated movements during printing, may disconnect, bend or break; for this reason it is really important to install a cable bracket that makes the connection fixed, exactly as for LK5 PRO. About that:

  1. Download the official Bracket Longer: https://www.thingiverse.com/thing:4818795
  2. Print it using 0.1mm Layer Height & 100% Infill as recommended settings
  3. Proceed to the installation as follows:
    • Unscrew and remove the 4 leveling knobs, remove the hotbed
    • Place the bracket on the metal plane, place the leveling spring in the bracket compartment
    • Assemble the hotbed again and screw in the 4 leveling knobs
    • Attach the cable to the Bracket using two fixing clamps
  4. Here is the final result:

2. Add a Mainboard Fan Protection Grid

The LK4 PRO's mainboard fan does not have a protective grid like that of the LK5PRO, so if you don't have a compatible metal grid then you can install a printed one. About that:

  1. Download the official Longer mainboard grid: https://www.thingiverse.com/thing:4957827
  2. Print it using 0.1mm Layer Height & 100% Infill as recommended settings
  3. Proceed to the installation as follows:
    • Unscrew the 4 mainboard fan screws
    • Place the grid
    • Start the 4 screws
    • Note: Due to the grid, you need to use 4 screws longer than the originals
  4. Here is the final result:

3. Move the Spool Holder to the Side

The LK4 PRO printer provides for the installation of the Spool Holder at the top; however, if you prefer to install the Spool Holder on the side of the printer, as for LK5 PRO, here is a practical upgrade to print and install easily:

  1. Download the official Longer bracket for Spool Holder: https://www.thingiverse.com/thing:4957817
  2. Print it using 0.2mm Layer Height & 100%Infill as recommended settings
  3. Proceed to the installation as follows:
    • Attach the original Spool Holder to the Bracket, using two bolts of correct size
    • Attach the bracket to the printer using at least two T-Nuts
  4. Here is the final result:

4. Upgrade to a Micro-Perforated Glass Printing Plate

Differently from LK5 PRO, which is equipped with a Micro-perforated glass plate, LK4 PRO has a glass plate covered with a rough ceramic film, excellent for having a perfect print adhesion, however it may often be difficult to remove the prints from the glass, as the adhesion remains unchanged even with a cold plate.

For this reason, it could be a good solution to proceed with the installation of a Micro-perforated glass plate also on the LK4 PRO, so as to obtain excellent adhesion during printing and easy removal of prints from the cold plate. In fact, the Longer Micro-perforated Latex plate is equipped with micropores, which with heat (starting from 60 °C) it "sticks" to the first printing layer, thus ensuring excellent adhesion as long as the plate remains hot. At the end of printing, cooling the micropores gradually it releases the printed surface, so the printed object will simply be placed on the plate and can be easily removed.

This upgrade can be got really easily, as it can be purchased at all our official Longer stores, at a very low price:

Final Result

With these upgrades, the Longer LK4 PRO can achieve improvements in several areas, including cable protection, cooling safety, filament setup, and printing convenience.

These modifications are simple and practical, allowing existing LK4 PRO users to improve their machine without replacing the entire printer.

For more accessories, spare parts, or additional upgrades, please visit the LONGER official website or contact the LONGER support team at support@longer.net.

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