Newbie guide to getting a first print

[Polygonhell]

As a newbie to 3D printers I have to say getting my first print was extremely frustrating, so I thought I'd share my learning what little there is of it here, hopefully it will help someone else work through the frustrations.

Getting a first print

The Slic3r Tutorials linked in the Slic3r forum really are a must read, but IMO it misses a lot of detail in regards to getting a first print, a process that can be extremely frustrating to people new to 3D Printers

You have the choice of PLA or ABS.

PLA has less shrinkage and as a result won't generally warp if you are not using a heated bed.
PLA has a nasty habit of expanding inside the PTFE tube in the hotend and blocking it. I disassembled my hotend more times than I can count before I got a decent print in PLA. I've found I still get PLA Jams if I don't run a fan directed at the hot end while printing.

ABS is relatively more forgiving, and in retrospect I'd recommend it for a first print.
ABS has significant shrinkage and without a heated bed any reasonably sized print will warp.
ABS appears to ooze less that PLA.

Honestly without a heated bed you will want to use PLA, but I think ABS is less error prone for a first print.

First level your table as much as possible, I personally use a piece of paper as a feeler gauge, position the bed by hand on either side, pop off the Z belt and adjust the screw put it back on measure/repeat. It actually doesn't need to be perfect, but the closer the better.

Without filament in the hotend turn it on set the temperature to (185 for PLA or about 235 for ABS), when it gets to temperature, take the filament and feed it in by hand, push some through the nozzle and verify it extrudes, tweak the temperature until it doesn't require a lot of force.
With PLA you have to be careful, if the temperature is too high, or IME without a fan just high for too long, heat soaks into the PEEK barel, and the PLA gets soft, expands and forms a plug blocking the barel, if it's too low and you push too hard the plug forms nearer the bottom.
If you block your PTFE tubing you need to take the nozzle off the hotend and either replace or find some way to clean the PTFE tubing.
ABS seems to be somewhat immune to this effect, I suspect it doesn't have the soft maleable state that PLA does before it melts, it's one less thing to go wrong for a first print.

Turn off the hot end and clamp the filament into the extruder, with 1.75 filament, it doesn't need to be very tight. I usually give it a tug and see if it moves, if it doesn't I consider it good.

Turn the hotend back on, and extrude some filament via the control software to verify that it's not slipping and you have a good starting point.

Setup Slic3r and slice the 20mm test cube, you'll end up with quite the collection of these if your looking for quality prints. I'd start with a 0.3mm layer height, going much lower requires the bed to be very level and much higher and getting the first layer securely on the bed can be an issue.

Now you need to set the home position, again I use a piece of paper as a feeler gauge, jog down until you can feel the paper touching the nozzle and set Z to 0 I usually enter G92 Z0 to do this, I then jog up off the bed and across to where I want x0/y0 to be and enter G92 X0 Y0.
Setting the Z height is by far the most error prone part and unfortunately one of the most important, the rods holding the table will bend allowing you to go below the tables 0, and it's easy to think you can feel the paper under the nozzle too early especially if there is some left over plastic slightly exposed from the nozzle.

Heat up the hot end and run the print.

Watch the first layer, especially the skirt go down, the way it looks will tell you a great deal about how level your bed is and whether the Z height is correct.
If it comes out looking very round, your Z is set too high, if it looks like a thin smear it's too low. Beware with PLA if you are too low the plastic will back up into the hot end and you guessed it cause a jam.
If the skirt is uneven from side to side then your bed isn't level.

At this point all you really care about is does it stick to the bed, if you get a decent looking first layer odds are you'll get a print, if you don't stop the print, adjust the Z zero position or re level the bed and try again.

If you are using ABS you can increase the temperature to aid adhesion to the bed, I can run ABS at 250-260 degrees without issues (and I usually do for only the first layer), be careful trying to do the same thing for PLA, if you increase it too much you get a jam....

Hopefully this will get you a print, and you can read through the Slic3r tutorials to start improving it.

I'd recommend when trying to solve issues is to change one thing at a time and watch the print at the suspect spot.
I had issues with backlash that caused very uneven layers, and my steppers were intermittently missing steps because of badly adjust trim pots.
The 10x10x40 tower is a good print to adjust temperature on, it's usually a 10x10 something blob the first time you print it.

[guanu]

its good to note that the temps you list are in degrees Celsius, not Fahrenheit...

[@CiDG]

I am finding that with MY ABS filament (and understanding that all plastics are not created equal) I am able to print quite well at 200 C. After a few prints I read this write up and tried the 235 C mentioned and I began oozing from the resistor hole in my hot end. Maybe a good idea to start around 200-210 and move up from there or use a known good/rated heat range for your particular filament.

[awander]

Note on temperature differences-I have 2 different meters with temp probes, and they differ in their reading by over 15 degrees Fahrenheit.

Which one is correct, i couldn;t say....if either one is correct!

[Polygonhell]

Temperature can vary a lot, as much because of how and where it's measured. I'm using the SeeMeCNC supplied thermister connected to a RAMPS board running repetier, as far as I can tell the temperature is accurate to within 1 or 2 degree, but that's the temperature of the thermister, not necessarily the point of extrusion which given the design is probably cooler.

As I say I usually push the filament through by hand and adjust the temperature until the resistance is reasonable. It's probably a little easier with PLA because it goes through a "Crystalline" state before it becomes extrudable.

200 is pretty low for ABS, but if it's working I'd go with it, in general you want to be printing with the lowest temperature you can that gives good adhesion between layers.

Ooze from the resistor holes is more an indication that something is creating a small gap between the Steel and AL parts of the hot end, a piece of foil perhaps?
To extrude there the plastic is creeping around the end of the PTFE liner and out through whatever gap.