Athena II Laser Engraver mod

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Athena II Laser Engraver Mod

Project developed by Shubham Jain & Abhijeet Patil

This Laser Engraver mod on the Athena II printer will allow you to engrave various designs on cardboard and/or wooden surfaces (acrylic material yet to be tested). You could also use the same setup for cutting sheets accurately enough upto 4mm. There are different steps involved to successfully install the DIY Laser Engraver on the Athena II. Detailed procedure and steps are listed below.

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Printing

1. Download this stl file [1] for the modified end effector that will be used to mount the laser.
2. Print the end effector

Print Settings

• Material used = PETG
• Layer Height = 0.2mm
• no. of top/bottom layers = 4
• Infill = 100% (you could give around 60-70 % to minimize the material)
• Printing Temperature = 210 C
• Speed = 80 mm/s
• No supports needed

Bill of Materials

Follow the link in the 'where you could find column' to see pictures.

Tools needed

Tools

S.No	Description	Where you could find
1	MOST Delta RepRap or similar RepRap 3-D printer
2	Precision Knife	Local Hardware store or Walmart
3	Allen key 5/64" or 2mm
4	Soldering Kit	Probably from a friend's lab or Maker's Space!
5	Card board and a small piece of wire (to mix and coat epoxy)	anywhere

Skills and Knowledge Necessary

• Freecad or CAD experience to modify or re-design the end effector.
• Knowledge of settings in Inkscape and settings in Franklin will help tweak few things.
• 3D Printing.

Assembly, Calibration and Inkscape Instructions

Assembly

1. Finish Printing the modified end effector from the above Printing step.
2. Steps 3 to 11 will be familiar to you if you built your Athena II yourself. If you bought an already built Athena II, follow the steps below carefully.The end effector depicted in the images is the original one. It is NOT our modified end effector. But the steps that involve cleaning magnet holes and inserting magnets work exactly the same.

3. 

   

   Clean the magnet pocket sides with a sharp knife, Do not over dress the pockets - magnets should fit snugly!. Use a small flat blade screwdriver to clean protrusions off the bottoms of the pockets - it's important that the magnets seat fully in them. Be careful to not remove too much material as the magnets should fit snugly in them. Clean all of the pockets in the end effector.
4. The magnets come in pairs with pairs being identified as those attracted to each others' same face, that is the sides with the larger diameter recesses should attract each other. Magnets should be placed in the end effector such that nearest-neighbors attract rather than repel. Magnets may be placed in the carriages without regard for polarity.
5. Magnets are placed in their pockets with the larger diameter opening facing outward. This is the surface that mates with the ball bearing on the end of a tie rod.

6. 

   

   Test fit the magnets in each of their pockets - they should fit snugly and all should fit flatly against the bottom of their pockets. Use the stack of magnets to insert and remove the end magnet during testing fitting. Do not let the magnets slam together!

7. 

   After ensuring the magnets fit properly in their pockets, remove them all from the pockets, keeping polarity in mind. Mix enough two part plastic epoxy to coat all the pockets in both end effector and carriages.

8. 

   Coat the interiors of all the magnet pockets with a thin layer of epoxy.

9. 

   Press the magnets into their pockets keeping in mind that the large diameter opening in the magnet points outward and the nearest neighbor magnets should attract each other in the end effector.

10. 

    Press the magnets all the way into the pockets using a non-magnetic tool or fingers (the aluminum handle of the precision knife works nicely).

11. 

    Clean epoxy out of magnet holes with the tip of a small screwdriver and paper towel. After curing, excess epoxy that remains on the face of the magnets can be removed with a sharp knife, but cleaning uncured epoxy is easier.

12. 

    Remove the small fan that came with the laser module. Place the fan on top side of the end effector and the laser on the bottom side. After aligning the holes, fix this sub-assembly using at least 2 2mm socket head bolts.

13. 

    You can now attach the whole assembly to the connecting rods of the Athena II printer.

Calibration

1. The actual end-effector is required for this procedure. If your printer is giving out successful prints, you can skip the calibration, but if you wanna re-calibrate, then start with the next step.
2. If you own an Athena II, you would already be aware of the basic calibration process, irrespective of whether you built it yourself or not.
3. But if you are new, please use this link. Go to section 2.3 on this page
4. Your printer is now calibrated for the Hot End.
5. Now that you know the hot end effector calibration process, let's move on to calibrating the laser module end effector.
6. After attaching the laser end-effector, home the printer. The base of the laser module used was 63 mm below the end effector. So, enter 120 in the Z position box. This should bring the laser base to around 50 mm above the bed.
7. Now, change the fan power to 0 from the Controls tab. This is an important step to switch OFF the laser.
8. Then, go to the Setup tab and find the Temps section. Change temp0 value to 0. It should be set to 50 by default. This is to use the laser as intended.
9. Now, place a thick (around 4-5mm) cardboard or a plywood sheet on the bed.
10. Next step is to Switch ON the laser. Remain alert for this step, fumes may start coming up due to laser cutting through the material. Enter 5 in Fan power under the Controls tab. Watch for any fumes and change back to 0 if anything starts burning. If not, change the focus of the laser so that a dot appears on the sheet instead of a dispersed patch of light.
11. Change Fan power to 0 again and now you're ready for engraving.

Laser Engraving Plugin Download

1. Download Inkscape Gcode Generator Extension from Github here [2].
2. Copy the files to the desired path and launch Inkscape.

Inkscape Instructions

1. Change document settings in Inkscape to Width=70mm and Height=70mm. This is the maximum area we could engrave at once. This is because the Inkscape generates Gcodes only for what's on the workspace and nothing off the bed. But, a delta printer like AthenaII works on polar co-ordinates and has its 0,0 position at the center of the bed instead of the left lower corner for Cartesian printers.
2. Import any image and resize according to the space avaiable. Then, "trace the bitmap" which can be found under Path menu. Press OK and then delete the image file that you imported.
3. Next, go to the Extensions menu and find the 305 Engineering plugin and choose the option that comes up under it. In the dialog box that appears, you can provide the directory for the file. Also, change the resolution, engraving speed as required and press Apply and Close the dialog.
4. Navigate to the directory where you just saved the file or else look for Quick Access in Windows Explorer. You will find a text file. Open this file and save it as a .gcode file. Now you're ready to Engrave!

Before starting to Engrave-

1. Turning Fan Power to 0 on Franklin is your Kill Switch.
2. Adjust fan power as needed for better etching. For 2-3mm cardboards, 20% power was enough for a good engraving.

Future Work

• A table of materials and thickness with settings for laser power to achieve the best results.
• A way to avoid the manual powering ON and OFF of the laser module via Franklin.

References

^{[1] [2]}