Nozzle touching/riding on print - WANHAO i3 Duplicator

[Glenjamin_J_Pi]

Hey guys,

I have an issue with my Wanhao Duplicator i3, where after it’s printed about 1 inch in height, the nozzle seems to be dragging on / riding on / touching the printed PLA.

As it prints you can see the whole extruded unit raising and lowering and it traces around the print shape. This is clearly affecting the print.

It lays the raft down perfectly fine and doesn’t seem to have an issue until the print reaches about an inch in height.

Does anyone have any ideas / suggestions on what might be causing this?

Any feedback would be greatly appreciated. I can’t seem to find anything anywhere.

Thanks guys,

Glen

[key23d]

Hi Glen,

could it be that something is blocking the movement of the printed?

Maybe a belt tensioner or something?

Kind regards, Guy

[amorton12]

You might be overextruding. Check your filament diameter and slicer settings for extrusion multiplier. Try doing a 100% infill 20mm test cube and see if the z dimension comes out flat or convex. If it’s convex, turn the extrusion multiplier down.

Also check your Z-couplers for play and ensure that they are aligned across the X-axis.

BTW, PLA doesn’t need a raft. Rafting is a way to make warpy materials like ABS work better with unheated build areas. PLA can be printed directly onto the build plate, painters tape, or gluestick on glass.

[RCole]

What are you using for a slicing program? I had that problem every time that I tried using slic3r. When checking through the gcode from slic3r, there is one spot (on every model) where the extruder was moved DOWN instead of UP. I never had that problem with Cura.

So… I would suggest to try a different slicing program.

[jj045645]

I’ve had this issue when printing parts with overhangs. When I have a PLA layer that doesn’t cool enough before the next layer starts I see this issue. I’ve solved the problem by either getting more air going across the printing platform with a fan on the desk, by upping the time that each layer gets to cure before the next layer is printed, or by printing various parts at the same time in order to let the layers on each part have more time to cool.

[KimBrown]

Hi Glen, I’m guessing the Prints you are doing are fairly small, or they have something like pillars or small areas that the printer spends time on. As the filament comes out of the nozzle at about 200’ if it’s working away repeatedly on a small area then the heat doesn’t have time to dissipate, so the temperature of that part of the print rises. As it rises, so the Plastic starts to rise. Some times if a print has a small area that it dwells on and it starts to rise, I try to hold it in place with the end of a 6" steel rule. Ok, so how can you avoid it, and not be sat there holding the darn thing in place.

There’s a couple of things…:-

1) print your self a cooling fan that cools the plastic as it comes out of the nozzle.

The plastic has to be HOT to meld to the plastic below it, so getting the right position for the fan

and the flow right can be difficult, but once you get it right it’s a God Send.

2) Lower your hotend temp by about 10’, it’ll help (it may not stop it, but if your not putting so much

heat in to a small area, it will take a little longer to Warp.

3) Sometimes you have corners that jut out on a print, and these seem to get affected more by the

build up of heat. You can counter act these by adding a pillar below the corner to hold it down,

then cut it off afterwards.

4) You can use a cooling fan, but be carefull here, as if the Fan cools down one section to

quickly, then it’ll warp the print.

5) But lastly, one of the very best things to do is have another structure (say a thin, narrow, column)

away from the print. What happends here is the printer puts a layer of plastic down on the print,

then has to travel to the column, print a layer on it, then return to the print. This gives the print

time to chill down a little, before getting another dose of molten plastic.

So the best things are, Cooling Fan blowing cool air near the nozzle.

Lower your temp if you can.

Put one or more columns around that the printer has to travel to… (I’ve used 4 or 5 before now).

Hope that all makes sense, and helps.

Good Luck,

Kim…

[cH4rF1r3]

Hi Glenjamin, I believe that you would want to include Z-lift into your slicer program, so that the extruder lifts during travel, it work wonders for small parts, that would easily detach due to the nozzle dragging along the print. Or in your case dragging and leaving lines etc.

Some guys from Reprap forum explained it better, here are some snippets:

“Cura has Z-hop and Slic3r has Lift Z, im setting it both to 0.1 mm, just enough for the nozzle not to hit the printed parts.”

“The Lift is set with your slicing software not on the printer. The printer does not distinguish between printing moves and moving moves. If your nozzle does not lift during a print, your slicer is not configured to do this.”

The original thread,

Nozzle does not lift during travel over the print

For your info, Lift Z is found in slic3r under >Printer Settings (Tab) >Extruder 1 (Left side Menu) >Retraction (Section) >Lift Z

For CuraEngine >Print (Tab) > Extrusion (Sub Tab) > Z Hop

I would recommend either inputting 0.1 mm or 0.2 mm, but for single layered items, like the stretchy bracelet (Stretchy Bracelet by emmett - Thingiverse), it is better to not use lift, as sections would be broken due to the lift, but anything else it depends case by case.

By the way, I’m using Sunhokey i3 Prusa 2015 with Fan Mod, and printing using ABS with heated bed, if you wanted to know =D, just leaving this here

[rucudo]

Check your x-axis rods. My Duplicator i3 top x rod is a fraction to short and allows the whole carriage to shift when it comes out of the sheet metal hole. It is very subtle to the eye, but you can feel when it is loose.

CAD files for Metric Two-Piece Clamp-On Shaft Collars.

McMaster-Carr

Printed a couple of these out and haven’t had a repeat issue.