What's going on with my print please

I'm using abs plastic heatbed 90 nozzle 230, 0.4 nozzle 0.2 1st layer height 0.20 layer height, bed clearance 0.08mm fielder gauge prusa i3 rework vet 1.5 I've tried tightening belts and changing bearings to iguana drylyn but nothing'g seems to have improved, alladvice welcome thankyou Andy

It looks like some overextrusion combined with poor z axis performance (not unusual with threaded rods). Have you calibrated the extruder? What is the actual filament diameter (measured and averaged, not nominal)?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks for the response I've calibrated the extruded it's probally give or take 3mm out, filament is 1.75mm says that on the box do I need check it ? also what can i do to improve the z axis without changing it ? cheers Andy

Edited 1 time(s). Last edit at 11/28/2016 10:34AM by Ontheedgeandy.

"give or take 3mm" isn't calibrated.

Actual filament diameter is almost never the nominal value. There are different ways of dealing with the variations. You can measure in multiple places and calculate the average or you can print a test part and measure that and use the result to alter the extrusion multiplier or flow value. I prefer measuring the diameter and calculating the average because you can then calibrate the extruder with the actual filament diameter and know that using actual diameter in the future will give consistent results without having to print a test part with every new spool of filament. See [reprap.org] for a good calibration procedure.

Improving the Z axis can be a real project. The problem is that threaded rods are always bent. As they rotate they put lateral forces on the ends of the X axis, the Z axis guide rails, and the frame. All those things deflect and cause small layer shifts that you see as Z wobble/banding in the print. People usually attempt to fix it by decoupling the lateral movement of the bent screw from the x axis and guide rails using printed parts designed for the purpose. Check Thingiverse for parts that fit your machine or for inspiration to design your own. Of course, such printed parts are band-aids and don't fix the real problems, but they can help. The next thing to do is to replace the bent screws with proper lead screws (and nuts) which are normally not bent. Beyond that you get into bracing or replacing the frame and switching to fully supported guide rails. By the time you're done you have a completely different printer.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

thanks for the good explanation really appreciated, whats causing the chimney to look like it does? also how can i improve the window on the boat it looks as though its sagging thabnks Andy

The window on the boat looks like your lacking proper cooling for PLA bridging. I found the blower type setups work a lot better than the fan setups. Or, your cooling system isn't running fast enough when it did the bridging of the top window.

Edited 1 time(s). Last edit at 11/28/2016 01:50PM by PDBeal.

The chimney looks too hot. A slightly heretical suggestion is to apply a little part cooling, assuming you have a part cooling fan fitted. The usual advice is not to use part cooling with abs, but if a small area is getting too hot then I would argue that cooling is what is needed. As an alternative, some slicers allow you to set an option to move the head away from the part if the layer time is below a minimum value, and for those slicers that don't, you can print a second object of the same height placed a good distance away from the first part in order to give each layer a chance to cool down.

The sagging window is called bridging. Bridging is difficult because the print head is extruding in free air. It's worth getting a test part designed just for bridging while you work on improving it. The main factors that impact bridging are temperature, speed, extruder calibration and specifying the correct nozzle size.

cheers James ill have a look into that then,would you say the print quality ive got is good or bad?? thanks Andy

Not bad at all. My benchys don't look much better, but everyone has different priorities for what they work on. I like functional parts, exploring different filament types and designing hot-ends, so I haven't spent too much time on trying to get the best quality surface finish yet. I guess that time will come. There are others on this forum that produce amazing quality prints that I can't even begin to match.

Doesnt look too bad for ABS honestly.
Try printing two at once and I bet it will improve the top.
How fast are you printing? in mm/sec. I normally go from 40-60 mm/sec for most of my ABS

thanks for the response im pretty happy with the overall finish just wanted to tweak a little. ill have a go at two benchys and put up a picture when ive done , probally be tomorrow now though. cheers Guys