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Anycubic Predator Print Quality

If you're like me, you've been underwhelmed by the print quality by the Anycubic Delta straight out of the box. It has artifacts on all sides of the print just like this:

So If you're interested in how I went from the above to the below, keep reading...

The main cause of the cross-hatching artifacts (as seen in the second photo of the stock prints) is from the Axis's not being smooth. This could be coming from a number of places, but the most likely is the rolling axis/tower carriages. I would strongly recommend you tear each tower down and rebuild one by one.

1. You will need the following tools:

• 2mm, 2.5mm, 3mm & 4mm Allen Wrench's.
• 8mm Spanner
• Pliers
• Adjustable wrench

2. Turn off and unplug the power from your printer. Place a Napkin/Tea towel or cloth on the middle of the printer bed. Gently lower the effector to the bottom of the bed and place the nozzle on cloth. This will prevent damage to your bed whilst you work.

3. Start with the left Tower.

• Using a 2mm allen key, Undo the two bolts that have the brass ferrules that hold the Delta arms to the carriage.
• Using a 2.5mm Allen key, remove the spring from the top of the carriage.
• Using a 4mm Allen Key, Undo all 8 bolts holding the tower to the top and bottom plates. 4 at the top, 4 at the bottom. It will rest on the stepper dampner until you take the weight off, disconnect the stepper cable and place on your workbench.

4. Now you have the tower on your bench, using an 8mm spanner, adjust the eccentric nuts until the "dots" are facing towards the VSLOT. This is the "Loose" position. The carriage should now be very loose.

5. Undo the 2x 4mm bolts that hold the feet on the bottom tower and set aside

6. Loosen the 4x 3mm Bolts that hold the belt tensioner in place.

7. Undo the wingnut that tensions the belt.

8. Undo the 2x 3mm Bolts that hold the tensioner to the frame and set aside.

9. Remove the belt from the stepper motor and the tensioner pulley. Set the tensioner pulley aside.

10. Remove the carriage from the vslot by sliding it to edge/bottom of the tower.

11. Clean the vslot with Acetone and then Isopropyl Alcohol. You will be very surprised with the amount of oil and dirt are on this. Mine made the paper towel black and brown. Once both sides of the vslot are clean, set the tower aside.

12. With the carriage upside-down, inspect each of the wheels for damage. Check that they spin very freely without hesitation and are not notchy in any way. If they are not smooth, clean and free of damage you need to replace them.

• If they have been done up too tight, you may be able to loosen them off and then gently re-tighten.
• The wheels must not be done up super tight. They should only be done up tight enough to not have any slop or play. If they are too tight they can apply pressure to the bearings and damage them.
• I personally removed and re-assembled every single wheel.

NOTE If you need to replace your wheels, most new wheels will not come assembled. When assembling your new wheels be sure to place a shim washer (which should be included) between the bearings inside the wheel. With this assembly you will be able to torque the wheel assembly on the carriage without worrying about damaging the bearings.

13. Ensure the eccentric nut assembly is this order; Bolt - Carriage Plate - Thick Washer - Eccentric Nut - Eccentric Washer - Wheel - Nyloc Nut. Note: some users have reported that the "Thick Washer" is now built in to the Eccentric nut. NOTE Eccentric nuts are used in the recessed bolt holes locations, whilst normal stand-offs are used in the non-recessed. PRO TIP The goal here is to also get all the wheels at the same height, as each other so the carriage is not skewed and they run true.

14. As with step 12, Ensure the nyloc nut is not done up too tight. Also ensure the "Dot" on the eccentric nut is facing away from the non-adjustable wheels like it was when you removed the carriage from the tower.

15. Position the belt so the carriage is half way between each end. Ensure there are no twists in the belt.

16. Flip the carriage over and slide it into the tower. The delta rod posts end is the end to go in first. carefuly align the wheels with the vslots so you dont damage your wheels and undo all your hard work.

17. Now we need to set the tension of the vslot wheels. It's imperative you work on one wheel at a time. I always "tighten" my eccentric nuts in a clockwise direction which is "away" from the stepper motors. You will need to turn the eccentric nut atleast a full 1/4 turn before it will be close to making contact with the vlsot.

• Tighten in small increments, removing the spanner each time and testing for left/right & forward/back slop/play.
• The carriage should feel smooth, if there is lots of resistance or if the carriage can't free-fall when the tower is lifted - its too tight.
• Once you've tightened one correctly, use the same proceedure to tighten the second. With both wheels tightened, the carriage should slide smoothly about its axis, but have absolutely no slop or play left/right and forward/back in the vslot groves.
• Take your time doing this, it's crucial this is done well and properly.

18. Ensure there are no twists in the belt. Slide the belt over the stepper motor.

19. Take the tensioner pulley you put aside from the earlier steps and put it below the axis carriage. Ensure the bolt hole is facing away from the axis carriage. Put the belt onto the idler bearings - ensuring that there is no twists in the belt. Gently twist the bolts to rotate the t-nut so it's in the locked position whilst still enabling the tensioner to move up and down freely.

20. Take the tensioner and wingnut that was set aside earlier and slide it into the frame. Tighten the wingnut into the bottom of the tensioner pulley so atleast 2-3 threads are in. Lightly tension the belt using your fingers on the tensioner, ensure it's square and tighten it down.

21. Move the carriage to the stepper motor. Tighten the wing nut until there is a low/deep note. Its important to not overtighten the belt as it will pull down on the stepper motor dampner placing the stepper motor on a slight angle. If its too tight, when you move the carriage about it's axis you'll feel a pulsating type sensation. Too tight can also place extra side-load on the bearings in the stepper motor and pulley and can damage the bearings. Inversely, too loose will give you backlash and affect print quality.

22. Take the feet you set aside on a previous step and insert the 2x 4mm bolts that hold the feet on the bottom tower through the feet and re-attach to the bottom of the tower. They dont need to done up super tight.

23. Reassemble the Tower onto the printer, connect the stepper motor cable first and ensure it doesnt get snagged when you put the stepper motor inside the frame. Tighten the 8x bolts with the 4mm Allen key.

24. Re-attach the delta-rod arms to the carriage using the 2x bolts with brass ferrules and a 2mm Allen key. Attach the spring for the extruder to the top of the axis carriage using the bolt and the 2.5mm Allen key.

At this point you can either re-level/probe the bed or continue on to the advanced modification.

Advanced - Electronics Modification

Follow this guide at your own risk. I take absolutely no responsibility if you damage your board and it no longer prints or works properly. I was at the point of replacing my board if this didnt work or if I blew it up in the process - either way I didn't care.

I did a lot of reading and investigation of my own after reading https://reprap.org/forum/read.php?178,763881. I feel that this post actually explains the problem very well. To see if i could get better results, I decided to try it. If you want to as well, follow along.

1. Unscrew and remove the top perspex cover from the printer.

2. Disconnect your motherboard board, remove USB Cable and the SD Card, Un screw it and remove it.

3. Locate the 3 reistors that re used on the tower stepper motors.

These resitors go to ground and are connected to the ROSC pin. If we refer to the a4988 driver manual we read that its in "Automatic mixed decay for all step modes except full step which is set to slow decay". This is because ROSC is grounded through a resistor (10kohm IIRC). We want to set it to be in mixed decay mode for all step modes. To echeive this we need to bypass or short the resistor.

4. You have a choice;

• De-solder and remove the resistor. Solder a piece of wire to short the ROSC pin to GND.
• Solder a piece of wire shorting the resitor, effectively bypassing it.
• Use some aluminum foil or copper tape/wire and short the resitor.

I de-soldered the resistor and shorted it with a piece of wire.

After you do this you must re-level/probe the bed.