Newbie print problems - excess plastic, nubs and removing supports

[chenobble 1]

Hi folks,

Using Cura 14.0.7 and with the firmware updated as of two days ago.

I feel like most of my issues are basic newbie problems but i can't see an FAQ anywhere so I'll go ahead and ask...

Just got my UM2 working after the temperature sensor broke the day I bought it and my first few prints are finally coming out.

I'm hugely excited by this but there are a few concerns I have, namely:

1. The support framework that Cura makes leaves an obvious grid pattern on the underside of my prints which takes some serious sanding to remove, obviously affecting detail quality of the model.

2. the model, even on flat surfaces, is covered in plastic nubs that also need sanding off.

3. Strings of excess plastic presumably from where the nozzle relocated with melted PLA stuck to it. These are easy to remove but may be indicative of other issues.

4. Removing the print from the glass bed requires a paint scraper and a lot of force despite liberal application of the provided gluestick before printing.

Bear in mind that I've yet to come to grips with the configuration settings (or even how to change them) of my UM2 so you may need to overexplain some things...

 

[skint 61]

Hey Chenobble

Welcome to the forum. Don't worry we are all noobs around here!

If you can, upload a few images of some of your prints and we will take a look.

Cura`s support structure isn't the best. If you can, try to avoid support as much as possible, by reorientation, splitting the part, etc. Also take a look at mesh mixer.

If you are unpatient ( like me ) then forcing the print off the heated bed is sometimes tough, even with the whack of a hammer! If you leave the printer to cool down a lot, they should just pop off quite easily.

 

[gr5 964]

I have only used Cura's support feature on about 1% of my prints. Like skint says, try other orientations, or just don't worry about it, or use meshmixer:

http://www.extrudable.me/2013/12/28/meshmixer-2-0-best-newcomer-in-a-supporting-role/

 

As far as "nubs" you need to post a picture as there are 30 possible causes and post all your settings (just save settings to file and post that) but in general slower speeds give you better quality. So you can either print it fast and get something useful/functional or print it slow and get something beautiful.

 

[gr5 964]

By the way I often think something will be impossible to print and it just - sort of - works...

Like a human with hands hanging down - the finger tips are printed completely isolated in the air and fall to the bed but somehow the printer eventually recovers and actually manages to print it anyway.

 

[chenobble 1]

gr5 - thanks - i'll try meshmixer!

Skint - I tried printing this model:

http://www.thingiverse.com/thing:98361

with some of the settings suggested on this site before I recieved these replies - I slowed the print speed to 40 and upped the quality to high but didn't think to turn off support. It seemed to reduce the nubs a lot but the strings are still there, details are somewhat blurred and I don't know what happened to the spear...

http://imgur.com/a/IdbTx#0

 

[gr5 964]

Wow - that's some serious stringing. Please don't post imgur pics. I don't think they maintain pics for 10 years and someone else might have the same question as you in the future. Please post it here on this forum.

Don't use those low/med/high quality things in Cura. They probably don't do retraction. You need retraction to remove stringing. Also you probably need to print that color of PLA 10C cooler than whatever you were doing.

The numbs might be from the model. It might have excessive polygons. I would reduce the qty of polygons to around 10k maybe (or at least reduce by 10X) by using this procedure - it can make the model come out MUCH better:

Meshlab:

http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab

 

 

[gr5 964]

Oh - and check "cool head lift" so you can get the tip of the spear to come out much better.