paeonius
Posts: 24
Joined: Tue Jun 17, 2014 2:23 pm

Re: under estimated print time / print quality

I wonder why the estimates are always around 50% off, i did a donut that estimates say 8 hours, when I started printing machine says its going to be 12 hours =(

your pics are broken, thanks very much for your help so far! if you're around melbourne australia I owe you a beer!
vOidward
Posts: 40
Joined: Thu Feb 20, 2014 9:34 pm

Re: under estimated print time / print quality

Updated with imgur links, guess dropbox doesn't like hotlinking.

Also, print estimates in-firmware are wildly inaccurate, they're a simple calculation of time spent printing divided by number of layers, so if the first half of your print has all the gcode, it won't care, it'll assume the other half will have just as much.
paeonius
Posts: 24
Joined: Tue Jun 17, 2014 2:23 pm

Re: under estimated print time / print quality

I agree that they are just estimates but makerware usually had accurate times, and when i upgraded to the sailfish firmware i was consistently coming under the estimates
I usually send the sliced image with the estimates to the clients and the under estimates allowed for reprints and problems
but 50% over is a bugger
vOidward
Posts: 40
Joined: Thu Feb 20, 2014 9:34 pm

Re: under estimated print time / print quality

Well you've got a difficult choice here, spend 6 hours printing with Makerware and get accurate estimates, or print in 2 and a half hours in S3D and do a bit of math (multiply by 1.3-1.5) to get the right print times.

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I reduced the quantity of supports, I set 62 as the default overhang angle, then deleted everything in the tube past curves since they're impossible to remove anyways. Interior of the tubes actually came out cleaner. Filament usage also down from 12m to 9m. Cleanup was also quicker and easier.

You can take a glance at the .factory file, maybe use it as the basis for future prints like this.
https://dl.dropboxusercontent.com/u/703 ... _2.factory
paeonius
Posts: 24
Joined: Tue Jun 17, 2014 2:23 pm

Re: under estimated print time / print quality

very nice print and thanks so much for the factory file! will use it as a reference! love that you are printing on straight glass! are you using hair spray?
vOidward
Posts: 40
Joined: Thu Feb 20, 2014 9:34 pm

Re: under estimated print time / print quality

Actually, it's an 3/8 inch clear acrylic sheet from a generic plastic supplier. I glue tabs on it so it fits in snug, haven't had issues with flatness yet.
I get 5 of these for the price of 1 Makerbot build plate, can toss them when they're too damaged. Also, 2nd side doesn't have engraved logos on it, so it's totally usable.

Acrylic gives me the least problems in terms of adhesion, and if you hit it with around a 1200 grit sanding pad after you use it on the printed sections, the surface stays totally clean and smooth for a long time.
I've tried glass and aluminium and a few others, the heat absorption of the surface just makes everything pop off without heating or some kind of messy adhesive.
paeonius
Posts: 24
Joined: Tue Jun 17, 2014 2:23 pm

Re: under estimated print time / print quality

thats awesome about the acrylic, i agree the heat absorption with glass is a bit of a problem, but ive found a good 3m Automative tape i use thats great for PLA to stick to

printed the donuts using your files and a key widget but having problems with the finish at the top layer =(
I used your factory file
do you think if i increased the layers on the top and bottom it would help?

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TenKOhms
Posts: 172
Joined: Wed May 14, 2014 3:04 pm

Re: under estimated print time / print quality

either up the top layers by 2-3 or bump up your infill a bit. Should give you a better finish
paeonius
Posts: 24
Joined: Tue Jun 17, 2014 2:23 pm

Re: under estimated print time / print quality

TenKOhms wrote:either up the top layers by 2-3 or bump up your infill a bit. Should give you a better finish
thanks for the suggestion, I was wondering how come makerware uses 10% for 0.2mm and 15% for the 0.1mm settings but most other slicers use a much higher infill%
vOidward
Posts: 40
Joined: Thu Feb 20, 2014 9:34 pm

Re: under estimated print time / print quality

The engine header prints I did had no issues with their surface like the ones you're showing. I'm 99% sure if I extruded either of those objects they'd come out looking close to perfect.

It looks like you're severely underextruding. This is probably not slicer settings related, though some settings might be able to remedy this.

How long have you had your Rep2? Are you using your Rep 2 with the default delrin plunger as the extruder? If it isn't an issue with the extruder, then your nozzle might have a blockage in it. Do you ever hear a clicking sound when it's extruding?

Do you have callipers to measure your filament diameter? Simply trusting what it says on the package isn't a good idea.

It also might be a case of this PLA liking higher temps, so you could try putting it back to 230, but I somewhat doubt this.
A quick fix for this might be slowing your prints down to 3000mm/min, though it'll obviously increase your print time.

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