First Print Woes

I'm totally new to the world of 3D printing. Reading this forum has given me a realistic appreciation of the steep learning curve ahead and great respect for the body of experience that the contributors bring to this technology.
I received my new Robo 3D printer last work and didn't waste any time 'discovering' it. I set it up, loaded the software and 'connected'. It took me awhile to figure out the auto leveling but that now appears to be working well. When I attempted my first print, there were no issues with sticking to the bed. The first few layers looked good …. and I was beginning to think that somehow I'd managed to sidestep all the problems that I'd been reading about ...Then it all went to hell.
My first PLA print attempt, a small, simple calibration box, turned out what appears to be a mini Brillo pad … After experimenting with minor temperature and speed changes, successive print results just got worse and worse. I've used Repetier and Matter Control and have tried various slice engines with similar results.
Can anybody help diagnose my problems and suggest some tweaks that might improve my newbie efforts to get a solid 3D print? I'd appreciate any suggestions. (see picture)

imac63

 

What temp are you printing at?

 

I kept the temp around 190. No heat on the bed.

 

Can you upload a picture of the bottom of one of the prints?

 

Clean your hobbed bolt as it looks like you're getting under extrusion due to it being clogged. Increase your print temp to say 195 and if you're still having problems then 200 then 205 then 210 and fine tune once you find a temp that's working pretty good. The temp does depend in the filament you're using and even different colours in the same brand can be different, and also the hotend. I'm using 210 with the Hexagon hotend for my PLA filament from 3dprintergear.com.au

As Montravont suggests you need to check the bottom of your prints to make sure the lines are stuck/squashed together but not looking like one solid smooth piece of plastic. This first layer is 50% of a good print. If you have a heated bed the suggested temp is 50-60 for PLA but I get the best results at 65. If you're printing directly into the glass bed make sure you wipe it down with methylated spirits before each print. This is all I do for PLA and have no sticking issues.

Welcome and enjoy the ride. Like you I knew nothing if the 3D printing world until I got my Robo at the end of January.

 

Oh, also decrease you retraction speed to say 10-15mm/sec to reduce the hobbed bolt slipping/grinding the filament. The retraction setting is what my focus is at the moment. I use Repetier + Slic3r but bought Simplify3D last night so it's all going to change, for the better as the consensus shows so fingers crossed.

 

I hope you can see this. For the most part the start off well with a few exceptions ...

 

Thanks Galaxius. I considered cleaning the hobbed bolt but figured that it hadn't had time to get clogged just out of the box. Thanks for the tips ... I'll try them all and let you know.

 

If that's the blue PLA that came from Robo w/ the printer, try running it at 205 degrees, 50-55 for the bed. And slow it down a bit.

Also, perhaps raise your offset a bit. It's hard to tell from those pictures, but it looks like you might be on the edge of too close to the bed. Out of curiosity, what is your offset set to currently?

 

You don't need to take the hobbed bolt out to clean it. Just open the filament guide, pull the filament out, clean the hob using a small stuff brush like an electric shaver cleaning brush. That's exactly how i do it and it's worth checking before doing a bigger print as you don't want it to fail just before it's finished because the bolt was already partially clogged before you started, trust me.

 

Montravont,

You must be psychic ... That piece of paper that came with the printer and said "set your offset to this .... " There was nothing inserted after "this". Something else I haven't messed with ... I've seen the consecutive settings but thought that it might be compensated for by the auto levelling. Wrong, huh?

 

Ian, see this thread for entering your offset.
http://forums.robo3dprinter.com/index.php?threads/entering-your-z-offset-in-mattercontrol.2595/

Mine actually came with 2 pieces of paper. One was blank for the offset, the other had the number.

To determine your offset, home your printer (it should home to the center) and then raise the Z axis in .1 increments (and count how many you did) until you can just barely slide a piece of paper under it. When the paper goes under go back down by .1 and that's your offset.

Sometimes to get the perfect offset you need to go by half steps. So if you count .8, your offset might work slightly better at .75 or .85. You'll have to tinker with it a bit to get it just right.

 

Wow ...
That's huge ...
One day on this forum and I'm a lot smarter ... You guys are great. I'll keep you posted.

 

Ian, You can also use a pointy exacto knife to clean any shavings stuck in the hobbed bolt. It takes time but you can poke clean each ridge with the knife.

If you are consistently getting any shavings at all in the bolt after each print then that is a big problem and will intermittenly cause missing extrusions. Either you have a clog, the temperature is too low or the hobbed bolt is garbage. In many cases it is the later and I would suggest that you get a good one from one of the Ebay vendors. You need to specify one that is 15mm from the bolt head base (not the end) to the hobb center. Do this and you will not regret it.

 

For example this guy allows you to specify the hobb distance: http://www.ebay.com/itm/Hobbed-bolt...972?pt=LH_DefaultDomain_0&hash=item3389d3b854 , and ships free.

 

and this one: http://www.ebay.com/itm/Hobbed-bolt...302?pt=LH_DefaultDomain_0&hash=item35cdb91c06

 

Thanks Steve ... Done

 

Ian,
All the comments on the temp being too low for your particular filament are probably the main problem. I have some PLA filament that works really great at 210C to 215C (Prototype Supply on Amazon). If I printed it at 180 to 190 it delaminates badly.