Frequently Asked Questions

Our experts are here to answer your 3D printing questions. If you don’t see your question below, email us and we’ll be sure to get back to you.

What should I check before starting a print?

Just like any machine or piece of equipment, it’s important to make sure all systems are functioning properly and are ready to go before use. We have created this Checklist to download and print as a reference for our customers. Here are the steps below:

1. Preheat the bed, extruder and enclosure (when used) to desired temperature. Ensure all systems are reaching set temperature.

2. Make sure nozzle is at least 20mm above the bed and manually prime the extruder to ensure filament is flowing through the extruder.

3. Home all axis. On the smoothie board, select “prepare” and then select “home all axis.” Make sure the nozzle moves to the front left side of the print bed.

4. Check air pressure in reservoir tank. Make sure the valve is turned to “on” and that air pressure is at a minimum of 60 psi. If not, use trader valve attachment in bike pump or shop air to fill tank.

5. Check hot end cooling fan and make sure it is turning properly. If not, turn off power and replace fan before starting a print.

6. If printing large PLA part, make sure vegetable oil cloth is wrapped around filament above the extruder.

7. Slice the file and save it to computer desktop. Filter the G-Code through‘s Simplify 3D app on your computer.

8. Connect USB to smoothie board on printer control box. Push file to smoothie board SD card, after transfer is complete remove USB and begin print from smoothie board.

What does a good first layer look like?

The filament on a successful first layer should look like a flat pancake, if it is too round that means the nozzle is too far from the bed and paper thin filament means the nozzle is too close. The first layer of your print is the foundation of the part and needs to adhere solidly to the bed.

Some common reasons for poor adhesion on the first layer are having too cold ambient air temperature, print speed is too fast for the first layer, the nozzle is either too far away or too close to the bed, or the bed may not be level.

If you are not achieving good layer adhesion, you can spray hairspray on the bed when using PLA or apply ABS cement (can be found at local hardware store) when using ABS. Try slowing down your print speed and turning up the bed temperature for the first layer, but make sure the bed is no hotter than 75°C for PLA and no hotter than 115°C for ABS. Return to normal print speed and bed temperature once first layer is complete.

Another tip is to increase the first layer height in Simplify 3D to help ensure a successful print. This increase should be no more than 75% of your nozzle diameter. For example, if you are running a .7mm nozzle with .2mm layer height, increase the first layer up to .25mm total layer height. Only do this for the first layer, not for the entire print.

What causes jams and how do I fix them?

Filament jams are a common problem with FDM 3D printing, and will cause under extrusion or halt printing all together.

Cause: The nozzle is too close to the bed. In this case, either raise up the z axis or lower the bed and make sure the bed is level.

Cause: Heat creep up the nozzle. Sometimes heat can creep up the filament in the nozzle, causing a bulge that cools and then prevents proper extrusion. First, check the fan to make sure it is pointing at the heat break/heat sync and then check to see if thermistor is properly in place. You may need to remove the extruder and clean out filament material that is clogged or simply replace the nozzle. (See how to replace a nozzle below)

Cause: Ambient temperature too hot for plastic filament, causing plastic to soften and ball up in extruder. To prevent this, make sure PLA is not printed in a heated environment and keep enclosure door open to prevent heat build up. If running ABS, polycarbonate or other high temperature plastics, make sure the cooling duct is functioning.

Cause: Nozzle not reaching temperature or temperature is fluctuating significantly. To check this, first do a PID tune (see PID auto tune tutorial). If that does not resolve the problem then replace the heater core.

Tip: When running a PLA print, be sure to have a cloth lightly soaked in vegetable oil around the filament tube above the extruder, especially for extended PLA prints. The oily cloth helps to lubricate the hot end, protecting it from heat creep. Only do this for PLA, as it has a higher friction rating than ABS or other higher temperature plastics.

What type of filament should I use?

Our 3D printers will run most open market plastic filaments. There are a variety of factors that go into deciding which plastic is best for your part, such as it’s end purpose/use, impact strength, heat resistance and dimensional accuracy. Here are some of the most common plastic filaments used on our machines and the advantages and disadvantages of each:

PLA: One of the easiest plastics to print out of, PLA is also one of the safest, as it is derived from renewable resources such as corn starch. PLA should be used for high accuracy parts and checking fitment on large prototypes because it is dimensionally stable, meaning it has a low shrink rate (compared to ABS or polycarbonate, which can have higher and more varying shrink rates). PLA does not require a heated enclosure and is generally an inexpensive filament. However, PLA cannot be used for higher temperature applications or end use parts because it is very brittle and is susceptible to warping if left in a warm environment, such as in an automobile, a foundry or even in direct sunlight.

Tips for PLA: For large format prints, make sure to use a vegetable oil cloth or paper towel wrapped around the filament above the extruder to lubricate the hot end. You should keep the ambient temperature below 110°F (43°C) when printing and keep enclosure doors open to prevent heat build up. The bed should be heated to 65°C and the nozzle set to 215°C.

ABS: Also one of the most common plastics in 3D printing, ABS is ideal for low-cost end use parts because its price point is similar to PLA but it is a much stronger plastic. ABS is not susceptible to damage from heated environments and is less brittle than PLA. ABS must be printed in a fully heated enclosure with a heated bed to prevent warping and to ensure good layer adhesion. Even if warping is mitigated, poor layer adhesion would result from printing in an open air environment. ABS is also prone to shrink, even if the part is printed in a heated environment. This means dimensional accuracy could be compromised. It is important to check measurements after print is completed and to allow enough time for the part to cool down slowly  before removing from print bed to prevent post-print warping and additional shrink.

Tips for ABS: We suggest allowing a printed part to cool anywhere from two to four hours in the enclosure after the print is complete. Removing an ABS part from the printer before it is completely cooled could result in increased shrink, cracking or warping of the part. If dimensional accuracy is crucial to a part, we suggest printing a “sacrificial part” out of ABS to test for shrink rates and then scale up the model in your CAD program accordingly to compensate for shrink before starting the print. You can also use ABS cement to help adhere the first layer to the heated bed if needed. ABS should be printed in a heated enclosure ranging from 70°C to 80°C, the bed heated between 110°C and 115°C and the nozzle set at 240°C to 250°C.

Polycarbonate (PC+PBT): Polycarbonate is an even higher temperature plastic and almost twice as strong as ABS. It is ideal for end use parts that must withstand a high temperature or high impact strength and it has a high rigidity. You can use pure polycarbonate filament or a blend, such as PC+PBT (our preferred filament). We prefer PC+PBT over ABS in our shop because it is stronger and stiffer. However, polycarbonate filaments are more expensive than ABS or PLA by about 30 percent. Polycarbonate filaments also face the same issues as ABS in terms of shrink and cool down time and it must be printed in a fully heated enclosure. While polycarbonate is stronger than ABS, it has a higher shrink rate, we have seen up to 5 percent in some parts.

Tips for Polycarbonate: As with ABS, we suggest allowing a printed part to cool anywhere from two to four hours in the enclosure after the print is complete. If dimensional accuracy is crucial to a part, we suggest printing a “sacrificial part” out of polycarbonate to test for shrink rates and then scale up the model in your CAD program accordingly to compensate for shrink before starting the print. Polycarbonates should be printed in a heated enclosure ranging from 75°C to 85°C with the extruder set to 265°C and the bed heated to 125°C.

PETG: PETG is a modified version of PET plastic, and is close to ABS in terms of strength, high durability and high impact ratings. PETG is very solvent resistant and has great layer binding characteristics, even when printing in open air or in an enclosure. Much like PLA, PETG is dimensionally accurate and has low warping and shrink rates, but is stronger than PLA. PETG also has a shiny finish and can be somewhat flexible. In terms of cost, PETG is more expensive than ABS and PLA, about 30 percent more. PETG is a versatile material and is ideal for prototypes and some end use parts.

Tips for PETG: If maximum layer strength is needed, we recommend printing with PETG in an enclosure heated to 45°C. The bed should be set to 70°C and the nozzle temperature should range from 245°C – 255°C.

Flexible Filament: Flexible filaments, such as NinjaFlex have rubbery characteristics and are ideal for water tight parts. The Bull Dog XL extruder, which our printers are equipped with, work well with flexible materials like NinjaFlex. However, special care must be taken when printing with flexible filaments, as they are prone to jams and should not be printed in a heated enclosure. Flexible material is harder to print with because the filament will wrap itself around the extruder if too much back pressure is developed while printing.

Tips for Flexible Filament: We recommend using a larger nozzle, such as .6mm or above and slowing down print speeds dramatically, to around 20mm a second. It’s best if printed in a cool, open-air environment with the heated bed set to 65°C and the extruder at 245°C. Too much heat will soften the plastic even more and result in jams.

HIPS: A dissolvable material, HIPS is typically used as a support material for a 3D printed model, but it can also be used as the main model material. HIPS does not chemically bond to ABS or polycarbonates, and can be dissolved away from the part with a chemical bath using limonene. When used as the model material, HIPS is considered an alternative to ABS because it has similar qualities as ABS in terms of strength and heat resistance but is considered safer because it emits less fumes.

Tips for HIPS: When using HIPS as a support material, be sure to set up a primer pillar on the print bed to ensure the HIPS is extruded on every layer, preventing heat creep and jams in the secondary nozzle. When printing with HIPS, heat the bed to 115°C to 120°C with the heated enclosure set between 70°C and 80°C. The extruder should be set to 245°C. For more on how to print with HIPS, see our section on Support Material.

What are different approaches to support material?

Support material is crucial when printings parts that have overhangs, and there are two ways you can approach the print: use the same material as model for supports or use dissolvable support material.

One of the easier methods is to print the supports out of the same material as the model and then break away the supports after the print is finished. This does not require dual extruders or a tool change, and thus results in faster print time because no tool change is required. There is also less set up time and a lower failure rate because only one extruder is being used. The downsides to this method are that it can be harder to remove and is more labor intensive, and you may not have as smooth of a finish.

Single Material Setup: Orient your part in Simplify 3D as you want to print it. Then click on “edit process settings” and check the box “generate supports.” Then go to “supports tab” and set your parameters. This is an example of our recipe we have found that works best:

Simplify 3D support material example

Simplify 3D support material example

Tip: You want to have an upper and lower vertical separation layer to make support removal easier. Horizontal separation from part should be at least the diameter of the nozzle.  Use care when removing support material from model and use sanding methods as needed.

Using dissolvable support material requires dual extruders and two types of filament: HIPS (high impact polystyrene) for ABS and polycarbonate prints or PVA (polyvinyl alcohol) for PLA filaments. An advantage to dissolvable supports is that it’s easy to remove because the support does not chemically bond with the model material, and it produces much cleaner surfaces requiring minimal finishing work. You can also easily break away this type of support instead of dissolving it and it does not require a separation layer in the print. PVA is relatively easy to remove from PLA parts as it only requires a warm bath to dissolve.

But there are several disadvantages to using dissolvable support material, including an increased chance of print failure if parameters are not dialed in. This method can also be expensive and messy if dissolving away HIPS using a Limonene bath, and some types of Limonene do not work well with ABS, such as d-Limonene. It is also not ideal for large parts because it will take days for the HIPS to soften and dissolve and you will need a large, corrosion resistant vat to contain the Limonene while soaking the part.

When using Limonene you must practice proper chemical handling and disposal, be sure to check with your local health department on how to properly dispose of Limonene.

Tips for printing with dissolvable support: Use a prime pillar during the print to ensure that support material is extruded on every layer, preventing support filament from baking in the secondary nozzle for too long and causing jams. This pillar can be set up in the support section of simplify 3D. Make sure the two nozzles are aligned, and run calibrations steps (see how to calibrate secondary extruder) before starting print.

What to do when running out of filament during a print.

It’s always best to make sure you have enough filament for your entire part before beginning a new print, especially with large parts that have a long print time. But we know that’s not always the case and you might find yourself running out of filament before a print is complete.

It’s important to know that the smoothie board does not have the ability to pause a print from the SD card. If printing directly from your computer, you are able to pause a print to switch filament.

If you find yourself running out of filament during a print, you can perform what we call a hot swap. First, make sure the new filament is ready to be fed into the extruder, and is inside of the enclosure if using one. The filament needs to be cut at a sharp angle and the end should be straightened to ensure easy passage into the hot end.

Next, go to the smoothie board’s main screen and turn the feed rate down to 10 percent. Once the buffer has passed 32 moves the speed will slow down, so this can take a while if swapping filament during infill printing. Be sure to watch the machine and the smoothie board to see when it slows.

Once it has slowed down, grab the bull dog extruder and press the filament-change button to quickly pull out the old filament. (Be sure to wear gloves if using a heated enclosure, the extruder will be very hot!) Once the old filament is removed, quickly place the new filament in the extruder while still holding down the release button on the extruder. Push all the way down until the new filament is extruding. Then go back to the smoothie board and return speed to desired feed rate.

IMPORTANT: If doing a hot swap inside of a heated enclosure, try to keep the door closed as much as possible to reduce the amount of heat that is lost. You want to act quickly, but safely while swapping filament. Again, we recommend wearing heat resistant gloves, especially when using a heated enclosure. Be sure to close the door and wait for the enclosure temperature to stabilize before increasing the feed rate, otherwise poor layer adhesion will result if feed rate is increased too soon.

How long should I wait to remove a part from the print bed?

Just because your part is finished printing doesn’t mean it’s ready to be removed from the bed, especially when printing large parts. Heat is still fluctuating throughout your part, on the print bed and in the enclosure. It’s important to let the part and printer cool down naturally before removing a part. If taken off the printer too soon, a part may warp, shrink or even crack due to sudden temperature changes. This is especially true for ABS and polycarbonate plastics.

PLA has the shortest wait time, because it does not require a heated enclosure and can be printed in open-air. Still, it’s best to wait about 30 minutes to an hour before removing your part from the print bed.

ABS and polycarbonate filaments (such as PC+PBT) should be left on the printer with the enclosure door closed for at least two to four hours, depending on the size of the part.

PETG takes less time, especially if printing in open air. If using a heated enclosure, wait two to four hours.

How often should nozzles be replaced?

With regular use of our machines, we recommend putting a new nozzle on the extruder once a month. This is because nozzles have a tendency to wear out or develop small clogs from burned plastic, which can result in under extrusion and poor quality prints. Replacing a nozzle is inexpensive, is easy to do and helps to maintain your machine and print quality.

In addition to regular wear and tear, you should always replace a nozzle when switching to a different type of plastic, such as going from  ABS to PLA, or polycarbonate to ABS. This is necessary because small bits of leftover plastic can become lodged in the nozzle aperture, causing jams and poor print quality.

Also, plastic filaments that contain carbon fiber or glass damage a nozzle at a much higher rate than other neat plastics (unfilled plastics) and should be replaced after each use. If you are using carbon fiber or other filled plastics frequently, we recommend buying hardened steel nozzles, as these are much more durable than brass nozzles and will not wear down as quickly.

Steps to replacing a nozzle:

1. Preheat the nozzle and hot end you wish to replace on the machine.

2. Remove any plastic filament from the hot end by manually priming the extruder and then manually pulling filament upwards and out of the extruder until it is fully removed.

3. Using a crescent wrench to hold the aluminum block and a 10mm open ended wrench on the brass nozzle, unscrew the brass nozzle while holding the aluminum block stationary.

4. Once the old nozzle is removed, manually thread the new nozzle onto the aluminum block until the threads catch. The extruder should still be heated.

5. Once the first threads are on, use the 10mm open ended wrench and the crescent wrench to finish tightening the new nozzle onto the aluminum block.

*Now is a good time to use the wrench supplied with the hexagon hot end to check and tighten the heat break threads into the aluminum block.

How to perform a PID tune

A PID tune is necessary when a new hot end, nozzle or fan is put onto a machine, or to address problems with fluctuating temperature. This test will finely tune the temperature values on the hot end and ensure that you have a consistent temperature on the nozzle.

(Before running this test, make sure pronterface and notepad++ are installed on your computer)

Step 1: Plug a USB cable from the machine’s control box to your computer.

Step 2: Open device manager in Windows, go to ports, find the smoothie board and the comm port number associated with it.

Step 3: Open pronterface and connect to smoothie board using the corresponding comm port.



Step 4: Once connected, you will see a text box in the bottom right corner of pronterface. In this area type one of the following according to filament and extruder being used:

e0 for primary extruder, e1 for secondary extruder

PLA – m303s220 e0 or m303s220 e1

ABS – m303s250 e0 or m303s250 e1

PC+PBT – m303s265 e0 or m303s265 e1

code-entry-barStep 5: Push “Enter” and wait for PID auto tune to complete. (It will run eight cycles and will take about 10 minutes)

Step 6: Once PID auto tune is complete, you will see three number values in the main text area next to the letters “P”, “I” and “D”. Write these values down and close pronterface.

Step 7: Open Windows Explorer and go to the SD card labeled smoothie board.

Step 8: Right click on “Config” and select “edit with Notepad++”

Step 9: Scroll down to hot end 1 PID values. Or type “control+f” to find PID values. Replace values with the determined values during the PID auto tune test in pronterface.


Find “PID” in notepad++


PID values in notepad++

Step 10: Save and close Notepad++ and unplug USB. Cycle power on the machine, ensuring all systems are off before restarting and beginning next print.