Help with calibration of new printer  

RE: Help with calibration of new printer

You still have some belt tension issues.  Belts need to be rather tight.  Not lug wrench tight, but enough there is no play.  Use a small fishing scale, and the belt should deflect 15/64" with about 8 ounces applied force. Slide the extruder to the left, the bed to the back and lift the lower belt at the mid point. 

Also, a common new build issue is the gears are not attached properly.  

Use this method to reset the drive gears.  

Flat First: Drive gears must be tightened flat-first.

1)   Start with both set screws fully loosened so the pulley is free to spin on the motor shaft.

2)   Align one set screw dead center with the flat on the motor shaft, slowly tighten the screw until it fully contacts the flat surface.

3)   Torque the flat set screw to spec.

4)   Now tighten the jam set screw, and torque it to spec.

Once tightened, never touch the flat set screw unless the jam screw is first fully loosened.

Why Flat First? Set screws have flat ends. If you tighten the jam screw first the set screw on the shaft flat doesn't fully contact the shaft, only one small edge of the screw surface is biting. Reversing torques can easily shift the shaft to a position the flat screw no longer contacts the shaft. This lets the jam screw wriggle loose. And after a while, vibration loosens the screws until the gear is free to rotate.

And, no LocTite is needed when following this procedure since the jam screw locks the assembly in place.  Old ME trick I learned about 50 years ago.

RE: Help with calibration of new printer

Thanks for advice

I did double check on gear screws and they both rly tight and one screw is on flat part.

Belts is where I have biggest issue and unfortunately I don't have scale that you mentioned.

No matter how hard I try to pool its just impossible to gain even one more section on belt on Y-carriage or X-carriage and both tensioners are at their limit.

At this point I dot know what to do next.

Here is another print I tried yesterday.

RE: Help with calibration of new printer

The frog looks pretty good - layer 1 is still  a tad too high (z-offset should be 25 to 50 um lower (more negative).  

You can get by with the belt as is - but at some point you'll probably want to find a fish scale or trigger pull scale and actually measure belt tension. 

And some unsolicited advice moving forward: finger prints are bad.  Never touch the bed surface with body parts: oils left will cause all sorts of issues.  When it happens, parts not sticking, soap and water is what works.

RE: Help with calibration of new printer

As recommended in video by Prusa I use Isopropyl alcohol to clean bed and so far had no issue with adhesion even more benchy actually removed some black paint and left bubbles in shape of print. No sure if this is normal.

Will try adjust first layer as you suggested.

But still Im no sure how can I tighten more belt, is there any trick o way that Im missing?

RE: Help with calibration of new printer

Alcohol is NOT a good choice for regular cleaning of the bed.  It is useful after a print to remove PLA residue, but doesn't help (and in some ways can hurt) with regard to body oils.

Here's my chart for cleaning:

Alcohol rinse: every few prints

• Gloves recommended.
• Once in a while, an alcohol rinse is helpful to remove PLA residue. It does not remove finger oils well.
• Pour a 5 cm puddle of 91%+ alcohol in the middle of the bed, with clean hands use a fresh paper towel to scrub the bed. Wipe up all the alcohol.

Acetone wash: infrequent

• Pour a 2 cm puddle of acetone on the bed, scrub it around with a fresh paper towel. It will evaporate fast as you clean. This step removes PEI oxides that form over time and with heat, and improves PLA adhesion to a like new state.

Hot Water wash: often, as needed, and after any of the above

• Handle the bed only by the edges.
• Wash the bed in hot water, use a fresh paper towel as a wash cloth, with a few drops of plain dish soap (Dawn, unscented, no anti-bacterial, etc.).
• Rinse well in hot water - if you have very soft water, rinse a bit longer.
• Dry the bed with a fresh paper towel.
• Handle the bed only by the edges.
• Place bed on printer.

Streak test: when contamination is suspected

• With a fresh piece of paper towel, and very clean fingers, dampen the towel with 91%+ alcohol, and wipe the bed side to side moving back to front, like you're painting it with alcohol. The alcohol should be thin enough on the towel it quickly evaporates. If you see any streaks, the bed is dirty and needs a wash.

RE: Help with calibration of new printer

With regard to the PEI showing delamination when removing a part.  When the PEI is fresh, especially when the sheet new and the adhesive hasn't cured fully, it is sensitive to delam.  Best to make sure the sheet is cool before removing parts.  5 minutes in the freezer is a fast cooling method useful for extreme cases, and be sure you flex the sheet to break parts loose with the least strain and effort.   This is the only time I touch the PEI, and that's only on the side I don't print on.

The delam bubbles will fade over time, they are reabsorbed and disappear. 

RE: Help with calibration of new printer

Belt tension is a subject of some discussion.  Too little belt tension shows as minor layer shifting and some acceleration artifacts.  Gates specs 2 pounds as the minimum tension for motion applications like the MK3.  Yet there is no good way to measure tension except the deflection method.  The motors are rated to 11 pounds axial force 12 mm out the shaft.  So it's also something you don't want to over do.   

Most just get the belts "tight enough" and live with it.  And that's probably good enough for now.