General 3D Printing Thread


 
I find that the best solution is to let the hotend sit at temp until there is no flow from the tip. At that point wipe off any extruded plastic and then start the print. It will take about 4-5 cm or so before any plastic extrudes, but you won't get any clumps built up on the nozzle. A clump on the nozzle can kill a print.
 
Tom Kole said:
I find that the best solution is to let the hotend sit at temp until there is no flow from the tip. At that point wipe off any extruded plastic and then start the print. It will take about 4-5 cm or so before any plastic extrudes, but you won't get any clumps built up on the nozzle. A clump on the nozzle can kill a print.
Click to expand...

That's pretty much what I've been doing, and I run a two layer skirt around the object to make sure the plastic is flowing nice before it starts printing the object.

I'm just now doing my first prints on Kapton tape in attempt to print my "Roto-Damper" without the rectangular pad on the base. So far I've been printing on glass with "Fructis Style Extreme Control" hairspray, which has worked pretty well for me in general up until I needed to print this round object with an extremely flat bottom layer. I'm pretty impressed at how shiny and smooth the bottom layer comes out on Kapton tape, with the hairspray there seems to be a slight haze on the first layer. The adhesion seems really good on the Kapton tape too, I'm thinking I might change over from hairspray to Kapton tape as a general rule...
 
I only print on kapton and as you stated, the results are nice. The only problem is it becomes annoying having to replace the tape when it gets damaged.
 
Tom Kole said:
I only print on kapton and as you stated, the results are nice. The only problem is it becomes annoying having to replace the tape when it gets damaged.
Click to expand...

Yah, I can see that. I only had a 1" roll so I had to put it down in layers, and of coarse it's not perfect, there are some lines in the print on the bottom surface. I wanted to do a test to see how well prints come out on Kapton tape before I spent the money on a wide roll, I decided to pull the trigger on a 7" wide roll so I can get smooth prints, and hopefully it will be easier to apply. I know getting the wide tape down without bubbles is gonna be a task as well, perhaps a squeegee might come in handy for that job? I'm still printing on the glass (Kapton tape on the glass), so I can keep a spare Kapton tape coated glass around in case I damage the first one....
 
The trick to putting it on is warm water with some dish soap. Just dip the tape in that and apply to the glass. Squeegee out any remaining bubbles and allow to heat on your bed for 15-30in before printing.
 
Tom Kole said:
The trick to putting it on is warm water with some dish soap. Just dip the tape in that and apply to the glass. Squeegee out any remaining bubbles and allow to heat on your bed for 15-30in before printing.
Click to expand...

I used to use pet tape. Now i just print directly on to the Borosilicate glass heavily coated with extra hold hairspray. The tape is still on the bottom side of the glass. :>

I did add a 3mm brim when printing the HM case with no curling issues. Bed temp 110. Orange ABS.
 
I've posted my servoZ endstop on thingiverse if any of you i3 cool kids want to try it out. You'll need the latest Marlin from git, and edit the autolevel section. On my machine the offset is X=20, Y=0, Z=-3.90 and don't forget to enable servoendstops
 
Bryan Mayland said:
I've posted my servoZ endstop on thingiverse if any of you i3 cool kids want to try it out. You'll need the latest Marlin from git, and edit the autolevel section. On my machine the offset is X=20, Y=0, Z=-3.90 and don't forget to enable servoendstops
Click to expand...


Does the probe need to endup the exact hieght of the extruder? or does it need to be a bit longer?
 
It needs to be at least as high as the extruder but it doesn't have to be exact. My probe ends up 3.9mm below the extruder tip when it is extended. That's the compiled-in offset I had referred to. I was trying to get it closer but the length of the servo arm is the limiting factor. I don't want the cutout for it to go into the switch holder area so that's as just about as close as they can come.
 
Yeah it resets the rotational matrix every time you home so you have to re-level every print. You see the whole process in the video above, starting at 0:11 and ending at 0:37 soooo 26 seconds? If you don't re-home your printer in your start gcode then you can skip it I think but what's 26 seconds? You can also skip it if your bed is already level and it just assumes everything is flat.
 
Supposedly people say you can use something to gently pry the tabs on the side of the switch apart and it will pop open, but after 20 minutes with various tiny picks and a magnifying glass I was getting nowhere so I grabbed it with pliers and twisted. The plastic broke instead of the lever, but it is in a non-critical area so it should work just fine. The switch is made by Canal and they do make them without the lever but I was unable to find any for sale.
 
Thanks to everyones help I was able to print a 20 x 20 x 10 mm cube without issue tonight.
My cube is actually 20.07 x 19.93 x 10.10 is there a calculator that will help me hone this in a little better?
I though I remember seeing one but cannot find it
 
NickAuxier said:
Thanks to everyones help I was able to print a 20 x 20 x 10 mm cube without issue tonight.
My cube is actually 20.07 x 19.93 x 10.10 is there a calculator that will help me hone this in a little better?
I though I remember seeing one but cannot find it
Click to expand...

I'd say you're ok and leave it alone. But if you were hell bent on perfection, take the desired length, divide by what you got, and multiply that by the steps you had in your firmware. Leave the z alone though. That should be calc'd based upon your screw pitch. Messing with that will lead to problems. If you are micro stepping on z, get rid of it and set it to full step. Then adjust your z steps accordingly.
 
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Nick,

+- 0.35% error is pretty good. +1 for what Tom said. At this point I'd say you should start to concentrate your efforts on learning slicer and fine-tuning your speed and acceleration settings in Marlin.
 
NickAuxier said:
Thanks to everyones help I was able to print a 20 x 20 x 10 mm cube without issue tonight.
My cube is actually 20.07 x 19.93 x 10.10 is there a calculator that will help me hone this in a little better?
I though I remember seeing one but cannot find it
Click to expand...
nice numbers

Next i would print

http://www.thingiverse.com/thing:12820

This will check how square your x and y are.

Then proceed to

http://www.thingiverse.com/thing:113160

Once you can do a decent bridge you should be able to print just about anything.
 
I have some prelim garolite results. I took my sheet of 1/16" machined garolite and attached to my bed with clips. The 1/16" is very flexible so it flattens easily. The surface is very similar to that of a pcb, as Bryan stated, just not as stiff. My first run was with ABS because I'm still waiting on my Nylon, but the results were pretty good. The ABS stuck down nicely but there was some slight lift at the corners. I'm going to repeat with a slightly higher bed temp next time because I measure my temps at the surface of the aluminum heat distribution plate and not at the build surface and I forgot to raise the temp slightly to account for the increased bed height and new material. The print releases as soon as the bed temp drops and the surface is pretty smooth. Not quite as smooth as kapton, but much smoother than a spray. If the next print meets my specs I'm saying goodbye to kapton forever.

I suppose I can try printing with a brim too, but I've never needed to do that before. Do any of you guys use a brim? If so, any issues with removing it?
 
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