Tip Wipe for Pegasus 8 Printer

Several years ago I installed octoprint so I could remotely monitor and control my printer. However, I still had to run to my printer before each print to remove the plastic that leaked from the nozzle. So I designed a custom tip wipe to remedy this issue once and for all.

Supplies

1x M3 threaded inserts
2x M3 socket head cap screws
2x M3 nylock nuts
1x Brass wire brush

3D printer
Soldering iron
Brass wire brush

Step 1: Design Concept

Looking for available space, I noticed that the bed is actually capable of moving past the nozzle. This makes the very front of the bed a great place to add a tip wipe, without sacrificing any of the current build space or having to construct an elaborate mechanism. A simple wire brush mounted to the wooden build plate should easily do the job.

I was able to find a cheap pack of brass wire brushes designed for rotary tools from Harbor Freight that should work for this project. By creating a clamp for the brush shaft, the brush can easily be replaced when it wears out, or we can even try different brush types later on. This will attach to the wooden build platform. Because the brush can be easily removed for maintenance or experimentation we don’t need to worry too much about making this mount easily accessible. Therefore, the mount will be attached to the wooden carriage beneath the build platform.

Step 2: Tip Wipe Assembly

Start by printing the brush holder. Click here to grab the file from Thingiverse. I used the following settings:

• Layer height: 0.15mm
• Infill density: 25% (grid pattern)
• No support

After completing the print, all that's missing from our brush holder is the threaded insert for our clamping screw. To install, we'll set the soldering iron to 400F and slowly sink the insert until it's just below the surface. This can also be achieved with a non-adjustable iron. *Please note: the threaded insert will push some plastic down into the hole. In order to clear this, thread the screw into the threaded side first, then remove and thread into the correct side.

Step 3: Printer Modification

To install the tip wipe, we'll need to disassemble the printer so we can modify the wooden build platform.

We’ll first remove any clamps or hardware retaining the glass. Next, we’ll remove the screws which hold the heated platform to the base of the print bed. I recommend removing each screw half-way before fully removing the screws to minimize the bending of the heated bed.

With the platform removed, we need to drill two mounting holes. I positioned the brush holder 2.2" from the right side of the holder to the right side of the build platform base. We don't need to be too precise here, as the brush holder will seat itself against the platform, and can float left or right without causing any issues. The holes are drilled using a 1/8" drill bit and the holder as a template.

With the holes drilled, fasten the holder using two M3 screws and nylock nuts. Reassemble the printer in the reverse order that we took it apart.

Step 4: Programming

In order to let the extruder nozzle clear the print bed, we’ll need to modify the software limits set in the Marlin firmware. To do this, we’ll need to go to the Configuration.h tab, scroll down to the mechanical settings section, and change the Y Max Pos. For my pegasus 8, I changed the limit from 200 to 230. However, double check your printer by moving the print bed to its max Y position, then move it by hand to its max safe position and measure the difference. This will prevent a potential crash later on. Finally, we'll need to write a brief bit of code to tell the printer to wipe the nozzle before the start of each print.

G28 ;Home
G1 Z15.0 F6000 ;Move the platform down 15mm

G1 X60 Y210 Z10 F2000 ;Move extruder over tip wipe

G1 Z5 F2000 ;Lower extruder into tip wipe

G1 X50 F2000 ;Wipe left and right

G1 X60 Y209 F2000

G1 X50 Y208 F2000

G1 X60 Y207 F2000

G1 X50 Y206 F2000

G1 Z10 F2000 ;Raise extruder to clear tip wipe

You may need to adjust the X and Y positions depending on the exact location of your wipe brush.

Once you have this dialed in the tip wipe is ready for use!