Calibration is one of the most important steps to a 3D print. If your bed is not level, the print itself will not come out level and will run into issues. To calibrate the print bed on your Mini 3D printer:
First power on and "home" the printer. Homing the printer means putting the printer in the starting position (or front left of the bed). This setting will be under the Move section as Home Axis.
After the printer has moved to the home location, power off the printer.
You should now be able to freely move the X-axis of the printer head as well as the Y-axis of the print bed. Move the printer head to each corner of the bed and make sure that a single piece of standard printer paper can slide between the bed and the nozzle with just a small amount of friction.
If the paper can't slide underneath the nozzle or if it does so without any resistance, adjust the height by using the included hex wrench to turn the screws at each corner of the platform. Turning the screws clockwise will lower the platform while turning them counterclockwise will raise it. We recommend checking each corner as well as between the corners and the center of the bed until the height is correct at all points of the platform.
Once your printer is calibrated, try printing a small, simple model such as a calibration cube to make sure the printer can put down a first layer and that the other layers stay even.
While printing, there is a motor that pushes filament into the extruder head. If you have your feed rate set too high, it may try to extrude more filament than can possibly pass through the nozzle opening. This can cause the filament to back up and clog or even cause the filament to grind into the gear. You can repair this issue by firstly slowing down the print to a more manageable speed - the maximum printing speed recommended being 55 mm/sec. Once the speed is set, you will need to cut the filament back and feed a new run into the printer.
Retraction plays a large role for extruding filament. If the retraction settings are set too high, the filament can begin to wear down and even get stuck on the feeding gears.
Extruder temperatures are a setting that may need to be changed for every print. Too cool and the filament may not extrude out, whereas too high and the filament will just leak out of the nozzle. You want to find a place between these two extremes. Try adjusting the temperature +- 5 degrees at a time (120 max for PLA).
A clog in the nozzle can cause filament to not come out at all or come out in thinner than normal strands. You can clear these by either pushing the filament in by hand once the head is preheated to try and push out any debris or use something harder like piano wire or a hand drill to clear out the nozzle. Please refer to this guide for steps on cleaning out a clogged nozzle.
The most common way to clean out a clogged nozzle is by inserting a wire through the print head to help push any stuck filament out. Two types of wire can be used here, 0.35mm thick piano wire or 0.28mm guitar string. In either case you will need to:
First preheat the print head.
Once preheated, push the wire in from above the heat sink. Please make sure not to force the wire through as doing so can damage the printer.
Gently use a sawing motion to clean out any remaining burnt filament.
Another method to clean out simple clogs from your printer is by forcing filament through to push out any clog and clean out any residue. In the 3D printer community, this is called the "atomic pull method". To do this:
Heat up your extruder to the optimal temperature for your filament (210°c for PLA).
When heated up, remove any filament that can be pulled out of the feed tube.
Take a small portion of your filament (we recommend using a filament with a higher melting point like ABS if you are cleaning out PLA) and force it into the nozzle until you only see the color filament you are feeding through.
Next, change the nozzle temperature down to around 90 degrees and allow the printer to reach temperature.
Once the temperature is reached, maintain pressure on the filament for at least 2 minutes.
Pull the filament out of the nozzle from the top to help clear out leftover debris in the process.
Repeat as necessary.
Should neither of these methods work, our last suggestion would be to use a small hand drill. The hand drill would need to go in from the bottom of the nozzle and be used in a slow spinning motion to clean it out. Again, please make sure not to force this method to avoid damaging the nozzle.
Filament must be primed into the extruder head for it to print properly. To help prime an extruder, you can print a skirt around a print. This is just a single line a few millimeters away from the print. It will push out any old filament and the extruder will be ready to start the print.
If you are using software that allows you to change your Z-axis start position, try changing it by just a portion of a millimeter to set the Z-axis further from the bed. This will in turn give more room for extruding filament to come out and adhere to the bed.
If you are not getting any filament coming out of your extruder head, it could be that your filament is getting stuck in the nozzle with a clog or that the filament is grinding at the feeding motor. Follow proper steps to clean out your extruder nozzle and make sure the feed gears are not grinding or slipping on the filament.
If your bed is set too close to the nozzle head, you could run into an issue where you are trying to extrude more filament than can fit in the small gap between the bed and the nozzle. Try calibrating the print bed with a little more room between the nozzle and bed.
Blue painters tape is the most common bed material used in the 3D printing community. Not only is it inexpensive, but it is easy to find and it works well. The tape works best when printing with PLA at standard temperatures. If you choose to use blue painters tape on your bed, you will need to replace the tape once it rips, breaks, or no longer allows prints to stick to it. Usually the tape comes off easily from the print bed but, if it does not, it is safe to use an adhesive remover. Once the bed is clean from your old tape, we recommend using 2 or 3-inch tape on the bed. You will need to lay the pieces of tape across the bed while not overlapping or having too much space between them. Once the tape is on the bed, we recommend running through calibration steps again as the tape can sometimes be thicker.
Kapton tape is the second most popular bed material out there. It is mainly used with printing ABS due to the properties of ABS plastics. If you use Kapton tape, you will need to follow steps to clean off the bed platform. Once the bed is clean you will need to size how much Kapton tape you need for your print. Start by evenly laying out one side of the tape and use a flat, solid object to slowly flatten the tape to the bed. Using something flat and solid, you should be able to push out all bubbles and imperfections in the tape.
Cleaning out nozzle and gears
The best way to clean out your printer is running cleaning filament through the printer after every few prints or when you start to notice issues in printing. This filament is usually a bit softer as well as “sticky”. This will pull filament particles out of gears as well as out of the extruder head.
If cleaning filament does not do the job, you will need to manually clean out your parts. The feeding gears on the Select Mini printer are easy to access and can be cleaned without removing any parts. The gear can be cleaned out with any small pick that can fit between the gear teeth. Another common option is using compressed air to help push out any stubborn debris. The nozzle is a bit more complicated to clean out, but the best option is using a nozzle hand drill or piano wire. Both of these options would go in from the nozzle tip and help push out any stuck, burnt, or dry filament. If your nozzle is still not extruding, continue to our guide on cleaning out clogs.
3D printers move a lot while printing and will rub metal on metal. Like any machine, it works much better when properly lubricated. For the X and Y-axis running on cross bars and bearings, we recommend using sewing machine oil. This works best and keeps everything running smoothly. You will only need to apply a single drop on each axis bar and slide the head or plate across the bar to spread the oil. For the Z-axis, the printer runs on a threaded screw-like pole. For this pole, we recommend (sparingly) using a PTFE-based grease. In general, the Z-axis should be maintained once every 6 months whereas the X and Y axis should be lubricated when you notice them become dry or rigid.
If the SD card is not recognized on the printer or if the files are not reading, it could be an issue with the actual card itself. The first thing we recommend checking is that none of the print files on the SD card contain a space in their name. This shows in the printer as an unidentified character and can cause issues. If none of your prints contain spaces, we recommend reformatting your SD card. To reformat the card, please perform the following steps for your computer's operating system:
Insert your SD card into your computer. If you do not have an SD card port, using a USB adapter will work as well.
Find the SD card in your Computer window under Devices with Removable Storage.
Right click on the SD card to bring up the menu options.
In the format window, make sure the format file is set to FAT32 and quick format is selected.
Connect your SD card to your computer. Using an external card reader will also work if needed.
Open your Disk Utility.
Search for your SD card on the left side of the window.
Click the tab labeled Erase.
Expand the Format dropdown menu and select MS-DOS (FAT).
Note: If you choose to purchase an SD card, please make sure that it is not labeled HC (High Capacity) as it may not be compatible with the printer. This means that the card must be smaller than 4GB in size.