5. 3D Printing and Scanning¶

Research¶

What are the common types of printers?

The three most established types of 3D printers for plastics parts are stereolithography (SLA), selective laser sintering (SLS), and fused deposition modeling (FDM).

Formlabs

How does a 3D printer work?

3D printing is part of the additive manufacturing family and uses similar methods to a traditional inkjet printer — albeit in 3D. Additive manufacturing describes the process of creating something in layers, adding material continuously until the final design is complete. This term most often refers to molding and 3D printing.

It takes a combination of top-of-the-line software, powder-like materials and precision tools to create a three-dimensional object from scratch. Below are a few of the main steps 3D printers take to bring ideas to life.

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Types of Filaments

1. ABS (Acrylonitrile Butadiene Styrene): Key Features: Strong, durable, impact-resistant, and can withstand temperatures up to 100°C.

Applications: Ideal for hard-wearing parts.

Challenges: Can warp, curl, and crack in open chambers without material profiles.

2. ASA (Acrylonitrile Styrene Acrylate): Key Features: A reformulated version of ABS with better UV resistance, making it 10x more weather-resistant.

Applications: Great for outdoor use.

Challenges: Slightly more expensive than ABS, but printing difficulty is similar.

3. PLA (Polylactic Acid): Key Features: Biodegradable, renewable, and easy to print, with more detail than ABS.

Applications: Best for general model making.

Challenges: Has a low glass transition temperature, making it unsuitable for high-temperature environments.

4. PET-G (Polyethylene Terephthalate Glycol): Key Features: Impact and chemical-resistant, food-safe, and 100% recyclable.

Applications: Great for durable and ductile parts.

Challenges: Slightly less stiff than ABS but prints better with similar performance to PLA.

5. PC (Polycarbonate): Key Features: High impact resistance, thermal stability, and dimensional stability.

Applications: Engineering-grade material used for tough, high-performance parts.

Challenges: Requires high temperatures for printing (290-315°C).

6. TPE/TPU (Flexible Filaments): Key Features: Mimic rubber or silicone for flexible parts like seals and smartphone cases.

Applications: Best for semi-rigid or flexible products.

Challenges: Difficult to print due to softness, but once mastered, they are durable.

7. Nylon: Key Features: Abrasion-resistant with high wear and impact resistance.

Applications: Ideal for permanent fixtures, casings, and enclosures.

Challenges: Requires high printing temperatures and specific printers.

8. CPE (Co-Polyester): Key Features: Better chemical resistance than PETG, making it suitable for mechanical applications.

Applications: Industrial uses like hoses and tubes.

Challenges: Requires high-temperature printing for optimal results.

9. PVA (Polyvinyl Alcohol): Key Features: Water-soluble, perfect for support structures in complex prints.

Applications: Supports for intricate overhangs and details.

Challenges: Must be dissolved in water post-print.

10. HIPS (High Impact Polystyrene): Key Features: Dissolvable in limonene, used for support structures.

Applications: Works well with ABS and PLA.

Challenges: Can be brittle, but dissolves without damaging the main print.

11. Resin: Key Features: Liquid material used in SLA/DLP technologies, producing more detailed prints than filaments.

Applications: Used for fine, high-detail models with specific properties (e.g., strength, flexibility).

Challenges: Requires SLA/DLP printers and careful handling due to liquid state.

12. Metal Filaments: Key Features: Composite filaments that combine plastic with metal powders, offering metal-like characteristics after post-processing.

Applications: Used in industries requiring unique mechanical and visual properties.

Challenges: Not solid metal, requires specialized printing processes.

Additive-X Summarized by ChatGPT

Common problems with a 3D printer and solutions

3D printers can produce amazing things, but they can also produce incredible disasters.

Whether over extrusion or blobs on the print surface, you can face various issues when 3D printing. The good news is that most 3D printing problems have simple fixes, and you don’t need to go back to school or buy a new printer.

1. Under and over extrusion Under extrusion problem

Under extrusion happens when the 3D printer doesn’t extrude enough plastic, leaving gaps between the perimeter and infill.

When the nozzle doesn’t extrude enough plastic, you will notice gaps between the adjacent extrusions of each layer. This impacts the print quality and compromises the structural integrity of parts, leading to mechanical failures.

Over-extrusion happens when a printer prints too much plastic, causing a build-up of excess plastic that makes parts look like they are melting.

The cause

The most common cause of under and over-extrusion is an incorrect extrusion multiplier – a setting in the software that specifies the rate at which your printer will extrude material.

Another common cause of under and over-extrusion is incorrect filament diameter, which affects the flow rate and interlayer adhesion.

The solution

You can solve under, and over-extrusion problems by adjusting the multiplier up or down in software and making sure the filaments you use are the correct diameter.

2. Stringing (hairy prints) 3D print stringing problem

Stringing is a common issue when printing at high temperatures, and it occurs when small strings of plastic are left behind by the nozzle, leaving traces. Plastic oozing from the nozzle also wastes material and increases print costs.

Stringing is most common when printing smaller parts and models, which decreases travel between the nozzle and the following location.

The cause

The most common cause is incorrect retraction settings. Retraction distance (how much plastic is pulled out of the nozzle) and retraction speed (how fast plastic is retracted from the nozzle) are common problems.

It could also be that the extruder temperature is too high – this liquefies the thermoplastic, causing excessive oozing.

The solution

Check the retraction settings on your 3D printer. Configure the retraction distance and retraction speed for the material you are printing. You can increase/decrease the retraction distance by 1mm to see improvements.

If the extruder temperature is too high, turn it down, even if it means going against what the material manufacturer says – your 3D printer might run hotter than it says. Experiment to find the best print settings.

You can also try different filaments to eliminate stringing. PLA is prone to oozing and stringing, while ABS is less prone to these issues.

3. Layer separation and splitting 3D printing problem - layers seperating

When layers separate, they split apart during printing, destroying the session. Each successive layer needs printing with perfect inter-layer adhesion. Otherwise, parts can split and warp, creating lots of material waste.

The cause

The common cause of layer separation is excessive layer heights, where plastic is pushed through in too large a volume. You want the layer height to be around 20% smaller than the nozzle diameter so that layers bond correctly.

Another cause of layer separation is low print temperatures, inhibiting thermoplastic chemical bonding processes. It’s easy to get caught when switching or trying filaments from new manufacturers.

The solution

Refine your layer height for the nozzle. We recommend a layer height 20% smaller than your nozzle diameter (e.g., a 0.32mm layer height for a 40mm nozzle). Try reducing the layer height and see if it helps.

If you print at too low a temperature, crank it up a little. Increments of 3°C are safe to try with most rigid thermoplastics.

Another top tip is regulating the temperature of your print environment. If your printer has a heated chamber, try heating it by 5°C.

4. Blobs and zits on the surface Blobs and zits 3D printing

3D prints are primarily judged by their surface quality, with blobs and zits hallmarks of either a low-quality 3D printer or an amateur maker. But don’t be disheartened – blobs affect everyone because they depend on settings.

Blobs and zits are common after turning a printer on and off due to variations affecting the extruder system.

The causes

Retraction and coasting settings can cause blobs and zits. If imperfections appear the moment the perimeter is printed, your retraction settings need adjusting to account for the distance between when the extruder stops and starts.

If your printer has a Bowden extruder, it’s helpful to avoid retractions so that it doesn’t have to reverse, although this can cause stringing (see above).

The solution

Adjusting retraction settings allows you to avoid minor surface defects like blobs and zits. If the defect occurs when the extruder comes to a stop, the coasting setting is helpful to switch off the extruder a little before it reaches the perimeter. Coasting sets the speed the nozzle moves when the extruder isn’t pushing material out.

5. Curling and rough corners Corner curling

You will likely experience curling and rough corners when you print high-temperature filaments. The corners and edges curl because the layers are not cooled rapidly, allowing them to deform and form curved shapes.

The cause

Curling and rough corners are common issues when the 3D printing chamber/environment doesn’t cool layers quickly enough. For example, high-temperature filaments are soft in the chamber and prone to curling if not cooled.

Another cause of curling is parts not adhering to the print bed, which causes mechanical stress within the layers leading to deformation.

The solution

Make efforts to cool layers more quickly. Setting your heated chamber to a lower temperature can solve the problem, or you can adjust the extrusion temperature to make the filament less liquid out of the nozzle.

If curling occurs when you start printing, it’s possible that your build platform isn’t level or the first layer is printing too fast.

6. Weak infill

Your 3D print’s infill is critical in its strength and rigidity. Infill is responsible for connecting the print surface to the interior, creating a semi-solid model. If the infill is weak, it can impact dimensional accuracy and integrity.

Nipping infill problems in the bud are essential to stem material wastage and ensure that all your models perform as intended.

The cause

Sometimes, 3D printers struggle with certain infills when fast print speeds overexert the extruder. Another cause is thin infill walls, which make parts lighter, weaken the infill structure, and make it snappable.

The solution

Try an alternate infill pattern and see if problems persist. Grid, triangular, honeycomb, cubic, and rectilinear are infills most 3D printers can handle.

You can also try printing with thicker infill walls, increasing print time but making it easier for the printer to work on complex shapes.

Lastly, try lowering the print speed directly. If you try to print infill too fast, the extruder can sometimes struggle to keep up.

7. Gaps between the infill and outline Infill outline gaps

Arguably the most unsightly 3D printing mishap, gaps between the infill and outline signify that something is up with outline overlaps. Sometimes, printing too fast can also reduce bonding, causing the infill and outline to separate.

It is critical that the infill and outline bond for aesthetic and mechanical qualities – gaps are weak spots, making them detrimental to performance.

The cause

The most common cause is incorrect infill overlap parameter configuration in software, which puts too little material between the infill and outline – when it shrinks as it dries, it pulls away due to a lack of plastic.

Gaps between the infill and outline are also caused by too fast print speeds, specifically when the infill is printed faster than the outline. This doesn’t give the infill enough time to bond to the perimeter, making it shrink away.

The solution

Dive into your 3D printing software and look for the outline overlap setting. It is marked as a percentage. For example, an infill outline of 12% means that the infill will overlap with 12% of the inner perimeter. Increasing the percentage level for a higher infill overlap improves bonding.

If the outline overlap isn’t the problem, refer to your print speed. Fast print speeds, where you print the infill faster than the outline – or faster than the nozzle likes to operate for the pattern – can create gaps.

Additive-X

Group Assignment¶

Printer Test In this test, a 3D Model was printed to with various types of tests to show the capabilities and the limitation of the printer. This model consists of an Overhang Test, Bridging Test, Support Test, Scale Test, Diameter Test, Hole Test, and Stringing Test.

Printing Ready Template From The Internet

Then we were assigned to choose a ready design from Thingiverse.

The design I chose was Army Truck Kit Card as shown in the image below. I downloaded the STL files and went to the printing lab to print the files.

3D Printer’s Software

The printer is operated by importing the STL file of the design to t its software. In this case, the machine was operated by BambuStudio

Before printing, the printer creates these lines on the bottom of the plate to remove whate might be stuck in the nozzle and clean it before starting the print.

Here the STL file of the design was imported and placed in the plate.

I chose Bambu Lab X1 Carbon printer as the printer I want to print with.

Here the printer is calculating the time and the amount of filament needed to print the model.

For this design specifically it needs 2 hours 9 minutes.

The printer used to print this model along with the team’s models was Bambulab’s X1 Carbon

Individual Assignment¶

Magnet Box Design

In this task we were given two pieces of magnets and were asked to design a box that can be closed with these magnets. The magnets I got had the length of 12mm and 5mm thickness.