Author: Jonathan van Heijzen

One of the most important parameters to adjust when slicing a 3D model for printing is the layer height or step height. This is the thickness of each layer that the printer will deposit on top of the previous one, and it affects the quality, speed and strength of the print. I would like to discuss some of the things to consider when setting a step height in a 3D printer slicer.

The first thing to consider is the resolution and detail of your model. If you want to preserve fine details and smooth curves, you will need to use a lower layer height, as this will reduce the visible stair-stepping effect that occurs when printing curved surfaces. However, if your model is simple or has large flat areas, you can use a higher layer height, as this will not affect the appearance much.

The second thing to consider is the printing time and cost. The lower the layer height, the more layers you will need to print, and the longer it will take to finish the print. This also means that your printer will be unavailable for longer. No big deal if you are a hobbyist, but if you have a hourly price associated with your printer it can really increase the cost of your prints. On the other hand, the higher the layer height, the fewer layers you will need to print, and the faster it will finish.

The third thing to consider is the strength and durability of your print. The lower the layer height, the better the adhesion between layers, and the stronger your print will be. This is especially important if you are printing functional parts that need to withstand stress or impact. However, if you are printing decorative or non-functional parts, you can use a higher layer height, as this will not affect the strength much.

There is no single optimal layer height for every print. You will need to balance these factors and choose a layer height that suits your needs and preferences. A good rule of thumb is to start with a layer height that is half of your nozzle diameter, and adjust it up or down depending on your model and desired outcome.

Also, consider “magic numbers.” For most hobbyist FDM printers ideal step heights are in increments of 0.04mm.

Orca Slicer is an open source slicer for FDM printers that is based on Bambu Studio, which is a fork of PrusaSlicer. Orca Slicer offers some unique features and advantages over other slicers, such as Cura and PrusaSlicer.

Orca Slicer Pros:

  • It has a sandwich mode, which prints the inner and outer perimeters alternately, resulting in smoother and stronger walls.
  • It has a precise wall feature, which adjusts the extrusion width to match the model’s wall thickness, avoiding gaps or overlaps.
  • It supports Klipper firmware and has a built-in auto calibration feature for all printers.
  • It has more granular controls over print settings, such as overhang slowdown, adaptive bed mesh, first layer print sequence, etc.
  • It has a stealth mode, which disables connections to BBL HMS (Bambu’s cloud service) for privacy and security reasons.

Orca Slicer Cons:

  • It is still in development and may have some bugs or stability issues.
  • It does not have as many printer profiles or plugins as Cura or PrusaSlicer.
  • It does not have a built-in model repair or analysis tool like Cura or PrusaSlicer.

Cura Pros:

  • It is widely used and supported by many printer manufacturers and communities.
  • It has a large library of plugins and extensions that add extra functionality and customization options.
  • It has a powerful model repair and analysis tool that can fix common errors and optimize print quality.

Cura Cons:

  • It can be slow and resource-intensive, especially when slicing complex models or using many plugins.
  • It can be overwhelming and confusing for beginners, as it has hundreds of settings and parameters to tweak.
  • It does not support Klipper firmware or sandwich mode.

PrusaSlicer Pros:

  • It is developed by Prusa Research, one of the leading 3D printer companies in the world.
  • It has a sleek and intuitive user interface that is easy to use and navigate.
  • It has a built-in model repair and analysis tool that can fix common errors and optimize print quality.

PrusaSlicer Cons:

  • It is mainly designed for Prusa printers and may not work well with other printers or firmware.
  • It does not have as many plugins or extensions as Cura or Orca Slicer.
  • It does not support Klipper firmware or sandwich mode.

Conclusion:

Orca Slicer is a promising slicer that offers some unique features and advantages over other slicers, such as Cura and PrusaSlicer. However, it is still in development and may not be as stable or compatible as the other slicers. Cura and PrusaSlicer are more established and widely used slicers that have more printer profiles, plugins, and tools. However, they also have some drawbacks, such as performance issues, complexity, or compatibility issues. Ultimately, the best slicer for you depends on your preferences, needs, and printer. You can try out different slicers and see which one works best for you.

Yesterday I wrote about working with TPU.

This material caused me so many problems in the beginning that I thought it might be worthwhile to talk about it in more detail today.

One of the pieces that I optimize is the tension put on the filament from my extruder. I use a dual gear extruder rather than an extruder with just a gear on one side. This increases the surface area that is in contact with the filament and allows me to put less of a “bite” on the filament, making it less likely to get deformed.

Additionally, I optimize the tension screw so that my gears just barely make marks on the filament.

The underlying issue that I’m trying to solve is that the material is soft. If I place too much pressure on the filament it can flatten out and then it won’t extrude properly or might even cause a clog.

Along the same lines, I optimize my retraction settings. If you have the option of using a direct drive extruder vs. a bowden extruder, you should do so. If you don’t, that’s ok. It’s not ideal, but we can make it work. With a bowden tube using normal PLA my retraction settings are normally around 6mm and 40mm/s. When I set up with TPU, however, I use 1-2mm retraction and no more than 20mm/s. Additionally, most slicers have a setting that limits the number of retractions in a section of filament. I typically limit the retraction to no more than 3 retractions per 10mm. This is to avoid grinding a flat spot onto the filament from repeated retractions as the part is being printed.

In my post yesterday I mentioned that I increase my temperature and reduce my speed, but I didn’t mention any specific values. It varies, but I normally like to run TPU or silk PLA that contains TPU at around 210-220 and I run it pretty slow, usually around 20-30 mm/s. These specific settings all require some testing and optimization, but this should give you a good starting point. The general idea is to make sure that the material is melted enough when it gets to the hotend that it won’t cause the filament to bind or bend. Same thing with the speed, if you try to push too much filament through the filament ends up bending and causing clogs.

Working with flexible filament, such as TPU, is challenging.

One of the main challenges of working with TPU filament is its high elasticity and low rigidity. This means that TPU filament can stretch and bend easily, which can cause problems with extrusion, retraction, and feeding. It can be similar to trying to push rope. It is advisable to reduce the retraction distance and speed, as well as the print speed, to prevent stringing and oozing.

Another challenge of working with TPU filament is its sensitivity to temperature and humidity. TPU filament can absorb moisture from the air, which can affect its print quality and performance. Moisture can cause bubbles, cracks, and warping in the printed objects, as well as increase the risk of nozzle clogging. To prevent these problems, it is essential to store TPU filament in a dry and cool place, preferably in a sealed bag with desiccants. Moreover, it is recommended to use a heated bed and an enclosed print chamber to maintain a stable temperature and avoid drafts.

A third challenge of working with TPU filament is its adhesion to the print surface. TPU filament can stick very well to some surfaces, such as glass or PEI, but not so well to others, such as blue tape or BuildTak. This can result in either poor bed adhesion or difficulty in removing the printed objects. To solve this dilemma, it is helpful to use a thin layer of glue stick or hairspray on the print surface to improve the adhesion. Alternatively, it is possible to use a flexible or magnetic build plate that can be easily detached and bent to release the printed objects.

One final challenge that I’ve experienced is that some TPU (or filaments with TPU in them) tend to expand when heated up. I normally like to warm up my machine for a few minutes before beginning a print. This allows for any expansion and movement to happen while the machine is sitting idle, rather than while the machine is printing. However, I’ve found that some TPU based filaments will burn and end up leaving burnt pieces in the nozzle, which end up clogging it. For TPU based filaments, I prefer to retract the filament approximately 100mm, then warm up the nozzle, and include a line of code in the beginning of my file that feeds the filament back into the nozzle. For this same reason, I also like to do a cold pull after each part that I print with TPU based filament. I just cut off the last 25mm or so of the filament. I have far fewer issues that way.

These are some of the challenges of working with TPU filament that I have encountered and how I have overcome them. I hope this information was useful for you. If you have any questions or comments, please feel free to leave them below. Happy printing!

Z wobble is a common problem in 3D printing that causes the printed layers to shift or wobble along the Z-axis, resulting in a distorted or uneven surface. Z wobble can be caused by various factors, such as loose screws, bent rods, misaligned couplers, or poor quality lead screws. To fix Z wobble, you need to identify the source of the problem and make sure that all the components of the Z-axis are properly aligned, tightened, and lubricated. Here are some steps you can take to reduce or eliminate Z wobble:

  • Check the screws that hold the Z-axis rods and lead screws in place. Make sure they are not too loose or too tight. You can use a hex wrench to adjust them if needed.
  • Check the rods and lead screws for any bends or damage. If they are bent, you can try to straighten them using a hammer or a vise. If they are damaged, you may need to replace them with new ones.
  • Check the couplers that connect the lead screws to the stepper motors. Make sure they are not cracked or worn out. You can use a screwdriver to tighten them if needed.
  • Check the alignment of the Z-axis rods and lead screws. They should be parallel to each other and perpendicular to the X-axis and Y-axis. You can use a ruler or a level to measure the angles and distances between them.
  • Lubricate the rods and lead screws with a suitable grease or oil. This will reduce the friction and noise and improve the smoothness of the Z-axis movement.

If you ever go online to 3d printing chat rooms or help forums, you will inevitably have seen someone describe a problem with their 3d print to which someone will reply “your nozzle is too close to the bed.” What does this mean and what should you do about it?

When the nozzle of a 3D printer is too close to the bed, it can cause several issues.

  • The nozzle can scrape against the bed.
  • The nozzle can drag against the extruded filament and end up dislodging your part.
  • The nozzle can drag against the top of the layer and create a very rough first layer.

If you notice any of these issues with your printer or with your print you have a few options.

  • You can adjust the Z-axis offset
  • Relevel your bed
  • Lower your bed (also requires releveling)

I see this question pop up sometimes in help forums and chatrooms. My experience with filament has been “you get what you pay for.” I’m all for lowering operating costs, but do it carefully.

Here are some of the risks you should be aware of:

  • Clogging: Cheap filament can contain foreign particles or impurities that can clog your nozzle or damage your extruder. This can result in poor print quality, failed prints, or even permanent damage to your printer. Clogging can also waste your time and filament as you try to fix the problem or reprint your model.
  • Fumes: Cheap filament can emit toxic fumes or volatile organic compounds (VOCs) that can harm your health or the environment. Some filaments, such as ABS, produce more fumes than others, such as PLA or PETG. Fumes can cause allergic reactions, respiratory irritation, headaches, nausea, or other symptoms. Fumes can also pollute the air and contribute to global warming.
  • Quality: Cheap filament can have inconsistent diameter, color, or strength. This can affect the accuracy, appearance, and durability of your prints. Cheap filament can also have poor adhesion, warping, or brittleness. Quality issues can compromise the functionality and aesthetics of your prints and make them unsuitable for certain applications.

To avoid these risks, you should use high-quality filament from reputable brands that have good reviews and ratings. You should also follow the recommended settings for your printer and filament, such as temperature, speed, and cooling. You should also print in a well-ventilated area or use a filter or enclosure to reduce the exposure to fumes.

While printing with silk PLA, I had a couple of difficulties. One of the things that I encountered was with retraction. Without retraction enabled, my prints were a stringy mess. However, with retraction enabled, my extruder would grind a flat spot onto my silk PLA.

My lifesaver, it turns out, was two settings inside of Cura.

The way that Cura applies these two settings can be translated as “do not retract more than two times until at least 10mm of filament has been extruded.”

Adjusting these settings proved to be very helpful and allowed me to finish the prints that I had been having trouble with.

If you are using silk PLA, you might have encountered a common problem: the extruder gear grinds a flat spot on your filament when you have retraction enabled. This can cause under-extrusion, clogging, and poor print quality. But if you disable retraction, you might get stringing and oozing. So how can you overcome this dilemma? Here are some tips that might help you.

  • Increase the extruder temperature. Silk PLA usually requires a higher temperature than regular PLA, around 210-230°C. This will reduce the resistance in the hot end and allow the filament to flow more easily.
  • I have also had success with reducing the extruder temperature to the very minimum temperature. When reducing the temperature the flow of PLA is slower, so a slower speed is also required to accommodate the lower temperature. This option allows me to disable retraction altogether.
  • Decrease the retraction distance and speed. Retraction pulls the filament back into the extruder to prevent oozing, but it also puts more stress on the filament. Try reducing the retraction distance to 2-3 mm and the speed to 20-30 mm/s. This will minimize the grinding and still prevent stringing.
  • Calibrate the extruder tension. The extruder tension is the force that the extruder gear applies on the filament to push it through the nozzle. If the tension is too high, it can cause grinding and flattening of the filament. If it is too low, it can cause slipping and under-extrusion. You can adjust the tension by turning a screw or a knob on your extruder. The ideal tension is when you can pull the filament out of the extruder with moderate force, but not too easily or too hard.
  • Use a high-quality filament. Silk PLA is a special type of PLA that has a shiny and smooth surface. However, not all silk PLA filaments are created equal. Some might have inconsistent diameter, impurities, or additives that can affect the print quality and performance. Make sure you buy from a reputable brand and store your filament in a dry and cool place.

I was printing a couple of things for my wife out of PLA+. Then my daughter wanted something printed in a silk PLA that contained some TPU. These are two very different filaments with very different properties. Just swapping filament spools and hitting “Print” would not have been successful. Here are the steps that I took to successfully swap between the two.

Step 1: Clean the nozzle

The first step is to clean the nozzle of your 3D printer to remove any residue of the previous filament. This is especially important when switching from a lower temperature filament (such as PLA) to a higher temperature filament (such as ABS), because the leftover PLA may burn and clog the nozzle when heated to ABS temperatures.

To clean the nozzle, you can use one of the following methods:

  • Cold pull: This method involves heating the nozzle to the melting temperature of the previous filament, then letting it cool down slightly, and then pulling out the filament with a quick motion. This should remove most of the residue from the nozzle. You may need to repeat this process a few times until the filament comes out clean.
  • Nylon cleaning filament: This is a special type of filament that is designed to clean the nozzle by absorbing any impurities. You can load the nylon cleaning filament into your 3D printer and extrude it at a high temperature (around 250°C) until it comes out clean. You can also use the cold pull method with the nylon cleaning filament for better results.
  • Needle or wire: This method involves inserting a thin needle or wire into the nozzle and gently scraping out any debris. You can do this while the nozzle is hot or cold, but be careful not to damage the nozzle or burn yourself.

Step 2: Adjust the temperature

The second step is to adjust the temperature of your 3D printer to match the new filament. Different filaments have different optimal printing temperatures, which depend on various factors such as the brand, color, and quality of the filament. You can usually find the recommended temperature range on the spool label or on the manufacturer’s website.

Step 3: Adjust the bed temperature

The third step is to adjust the bed temperature of your 3D printer to match the new filament. The bed temperature affects how well the first layer of your print adheres to the build platform, which is crucial for preventing warping and curling. Different filaments have different optimal bed temperatures, which also depend on the type of build surface you are using.

Step 4: Adjust the speed and cooling

The fourth step is to adjust the speed and cooling settings of your 3D printer to match the new filament. The speed and cooling affect how fast and how well your filament solidifies after being extruded from the nozzle. Different filaments have different optimal speed and cooling settings, which depend on their viscosity, shrinkage rate, and strength.