Newbie - initial layer problems

I got a Mini for Christmas and have done a few prints on it but I’m seeing a few consistent issues which I would appreciate some help with.

I’m a newbie so not really done any printing before. I’m using colorfabb ngen filament and standard ngen profile in Cura - standard prints.
I have tried a calibration test piece on high quality settings and it’s pretty much off all over the place but the main problem is the initial layers.
I have done some searching and reading of posts on the forum and picked up some tips but I’d like to make sure I don’t damage my new printer, hence I’d like specific advice just in case I mess something up!

Cura settings for ngen:
pritt stick over bed as advised

  1. After bed levelling, when it starts to print it doesn’t extrude any material to start, or intermittent, which is just about okay as by the time it’s done the outline it’s sorted itself out but I’ve been doing several pieces so it’s got time.

  2. The initial layers seem to be squashed? a little so they end up wider than they should be. I printed some tetris style puzzle pieces (fit together into a cube) and all the bottoms were wider than the rest on the first two layers. I had to sand them down to fit into the box.

I also printed the makerbot robot as something a bit more fun and although the arms are wonderfully articulated, the legs are not (these were printed first) and I had to cut them loose. The lower joints don’t work at all.

I also printed a calibration test file and that is also way off. Every dimension is off by at least 0.5mm though it seems to get more accurate over larger dimensions.
It’s supposed to be 50 x 30 x 2mm. Mine is 50.63 x 30.58 x 1.42mm. The holes are supposed to be 3mm, 4mm, 5mm. Mine are 2.5mm, 3.52mm, 4.29mm

I printed a couple of filament clips and although the hole is just about 3mm at the top, there’s no way it’s 3mm at the bottom. You can see it’s way off.


  1. How do I print a wider outline so I can get the extruding working properly?
  2. How do I calibrate so that the printer does better first layers?

I’ve attached photos of some of the problems.

Any help appreciated.


The default Cura settings I looked at over-extrude the first layer. This is done to make it more likely that the print will stick to the bed well. Switch to advanced settings and lower the first layer % to 100%. Then measure the height of the first layer, or the skirt. It should be the same as the setting in Cura. Note you need a micrometer to do this, as you’re measuring 0.4mm or so. I think the default is 0.423mm or something like that… The first layer height is easy to adjust in the machine settings under Z-Offset. You want to adjust the extrusion amount and Z-Offset to get the first layer height as close to perfect as you can. Ideally, you do an extruder E-steps calibration to make sure the extruder is moving the right amount, then measure the filament and put that in, then dial in Z-Offset to get the height perfect.

You should also be measuring the filament diameter and putting that in Cura. Every filament is a bit different.

If you don’t have a micrometer, get one. They are pretty cheaply available at auto parts stores and places like Harbor Freight. And they are absolutely required if you want to tune the printer.

For more outlines, just increase the number in Cura’s advanced settings. It might be hidden in a “…” button. I don’t have it installed on this computer, so I can’t double check. If you haven’t found it later I can check at home. I also like to have it extrude an “anchor” in the corner to prime the nozzle. I do that by modifying the start gcode. It’s simpler to just have it print a couple more skirt passes though. :slight_smile:

To make test prints faster, there are a bunch of calibration prints on Thingiverse and others. Just use a 10mm calibration cube or similar to start with. Once you get the tuning done, things like the printed joints work great. I like this one as it tests a few things with a short print.

For first layer height, you can cancel the print after the first layer, speeding up the process a bit. :slight_smile:

Thanks very much. That’s a great help. I’ll do a tester tomorrow.

I eventually found the skirt settings under ‘expert config’ and it was set to over extrude. Lulzbot instructions said to use the ‘quickprint’ settings until you know what you’re doing but that said, it’s also not quite printing right so obviously need to adjust things in ‘expert’.

I have a digital micrometer and used that to measure the calibration test print so I’ll try that on the first layer.

I have a few test pieces I can try tomorrow that are fairly quick to print.

I’ve done quite a bit of testing today.

I have checked the extruder calibration - it was fine. Exactly 100mm was fed through.
I have adjusted the initial line width to 100%
I checked the filament diameter and it varies quite a bit so I’ve put in an average.

The Z offset calibration is proving trickier. I checked the first layer and it was 0.35mm so I set the Z offset as 0.075mm but the next first layer it printed was at 0.31mm - 0.35mm so basically the same. Not sure if I’m doing something wrong?
I’ve put it back to 0 for now.

It printed the piece you suggested ok but there is variation in sizes and wall thickness still. Some bits are perfect but other bits are a bit off. Either wall thickness over 1mm or size of object a little too big.

I’ve tried adjusting the filament dia up another 0.05mm to see if that helps and trying another print.

EDIT: Print 2 turned out slightly better. It’s still got a very slight lip at the bottom of the print but it’s getting closer to correct.

I noticed that the filament was bubbling / popping a bit when I extruded some to make sure all was ok before printing. Is there any reason for this to happen other than water absorbed into the filament?

How much variation do you have in filament diameter? Ngen is pretty good, I would expect +/- 0.1mm maximum. Make sure you are measuring at 90 degrees and get a consistent number in the same spot.

If increasing the filament diameter in the software helps, try turning down the extrusion percentage a little.

Popping sounds are almost always moisture. I wouldn’t expect that to be a big problem with ngen though.

For Z-offset, try a larger value to verify its working. 0.2mm should work as a test.

Thanks very much.

I had read that the ngen was pretty consistent so perhaps I was measuring it wrong. I did try several times but in different locations and perhaps had it off square when doing bits round the reel. I’ll have another look at that.

I’ve got the ngen in a vacuum sealed bag with some silica gel now so that should stop any further moisture.

I’ll have another play when I get a chance.

One thinig to check when you are calibrating your e-steps: the workflow description says to use a speed of 100 when feeding your 100mm of filament. This is too fast, and will generally end up with too high an e-steps setting, resulting in over-extrusion. Try feeding your 100mm at a speed about 40 during the e-steps calibration. That speed more closely approximates a typical printing extrusion speed and will give more accurate results.

Thanks John Mc. I watched a video on YouTube before doing it and that recommended a speed of 50 so I did it at that. Seemed pretty slow and for that, the extrusion seemed very accurate.

I have got it printing much better. I checked the ngen dia again and set it to 2.87mm and reduced the flow rate to 98%. I printed a fidget spinner and that seemed pretty close to size but I need to print another test calibration piece to check measurements.

Good to hear it’s printing better for you

A speed of 50 should be fine. 100 seems to just bee too fast. Someone explained to me that the faster speed builds up back-pressure in the extruder, which can cause missed steps and an inaccurate calibration. You probably already know this, but reducing your e-steps by X% has the exact same effect as reducing your flow rate by that same percentage. I usually try to dial my e-steps in very close, and get my average diameter very close, then do any short-term fine tuning with the flow rate.

There are links on here somewhere to procedures for getting it even closer, but the slower speed usually gets you fairly close for most purposes. Here’s one such guide: Triffid Hunter’s Calibration Guide. (I did not bother with the calcualtions for x, y, and z steps. They seem very accurate as set with the machine. Since the machine also came with the e-steps fairly close from the factory, I did not go to the trouble of removing the hot end in his “E-steps - Measure” section. I just dialed it in using the slower speed with the hot end in place, as you have already done. His descriptions in the sections I skipped are interesting, however, if you want to understand better what is going on. Much of the “Z-height” section does not apply to a machine with auto-bed-leveling/bed-height like the Mini.) The real value in this guide for me was the description under "E-steps Fine Tuning"

Another very helpful thread: A Strategy for Obtaining Great Prints.

You also mentioned bubbling and popping, which can be a sign your filament has picked up a lot of moisture. The “Great Prints” thread has a good post about filament storage methods here. I used the 5 gallon plastic bucket with the screw-on lid as recommended by the poster. It works very well in the classroom setting (20+ 5th & 6th graders poking around in it). and it’s also compact: I’ve had four 1 kg spools in it, along with some other small items and a couple desiccant packs. (After ordering the special screw-on lid, I found it was also available at my local hardware store). I also made my own desiccant packs from Fresh Step Crystals & coffee filters, as explained in that post.

Here’s another thread on Filament Storage where ScottW shows an option for another container which holds 10 spools: 44 Quart Ziploc WeatherShield Storage Box. It has a gasketed lid, and clips that hold the lid closed securely, providing a tight seal (which means your desiccant packs will last a whole lot longer before needing to “recharge” by putting them in the oven to dry out). Note that there are similar-sized containers available, but this one works very well, since the dimensions work out nicely with the spools. The thread has pictures of the 10 spools packed in.

Thanks John.

I’ll check out those links. It seemed spot on for the e-steps. I didn’t know that e-steps and flow percentage did the same thing. I’m still learning and have a couple of videos bookmarked on YouTube to watch too on setting things up.

I have looked at the ‘Obtaining great prints’ thread and it’s very useful. Just need to get to grips with all the technical aspects.

I didn’t have any bubbling or popping the last time I printed so perhaps it was just a section of the filament. I’ve been careful to keep it in the house rather than the garage between prints with desiccant in the bag and I have now got it stored in a vacuum bag with desiccant.

I only have a couple of reels at the moment but if I get more I might look at a larger container as it is a bit of a faff sucking the air out of the bag after each time I use it. I’m in the UK.

For just a few spools, you could probably stick to the 5 gallon plastic bucket. They sell for about $5 at my local hardware (the same hardware store uses similar buckets to sell pain in 5 gallon quantities, so if you know a painter, you can probably get one for free). The original snap-on lid will work, but the screw on lid is certainly easier (the rim snaps on like the original lid, but once on, that rim stays on, and the center section unscrews for access). Less hassle than vacuuming out a bag each time. The seal must be pretty good, because I’ve had the same desiccant bag in there for about a year now and it still hasn’t needed a recharge (I check the weight of the desiccant bags from time to time to see how much moisture has been picked up).

This bucket has four 1 kg spools and a couple of desiccant bags. There is room for 1 more spool in it.

Thanks John. I’ll have a look out for something similar.