Picking a 3D Printer?

Picking a 3D Printer? Here is what you need to consider

Closed or open source
Some printers only accept filament from their own company. This preventing you from using 3rd part filaments with it. However, they are typically very well calibrated to their own filaments. This preventing you from having to set the machine up yourself to suit the new brand. This is often simpler for the novice user.

Self Assembly Vs Preassembled
Not all printers come assembled. Self-assembly kits are often cheaper as manufacturers do not require to assemble, calibrate and test the machine. However, this takes some confidence and skill from the customer who is taking on the responsibility of making it themselves. It also assumes that they will have the necessary tools and skills.

Software Compatibility and Connectivity
Printers come with their own dedicated software, this can open .stl models, slice them then be communicated to the printer. Check if it is compatible to PC or Mac.
Many printers operate by USB connection (typically type B)
Some printers offer an Ethernet connection
Some printers operate wirelessly, using a wifi connection. They can link to computers or often to smart phones
Some have USB or SD card slots so you do not have to rely on an external computer during the print

Warranty and Maintenance costs
How long is the warranty also what does it include and exclude? Consider how much are replacement parts? The most common piece needed replacing on a 3D printer is the Hot End. How much are they? Consider buying some in advance so that your production is not slowed down.
Display screen
LCD screens will often show more information about the print e.g. bed and extruder temperature. If you are looking for a cheaper printer consider something without a high-tech screen. Anything with a touch screen is automatically more expensive as it will be offering extra features

Additional features
On board camera: to keep an eye on prints, to monitor their progress or to record the process and to take photos of the final print.
Material recognition: some printers are closed source systems and will not let you load other materials into it. This can be useful if you accidentally try and use the wrong material with the wrong print head though. It can potentially prevent damages.

Filament types
Your standard printers will take PLA and ABS. If you are looking at more complicated types of material, you will need to check if they are compatible.
Aesthetics: Is the printer being put somewhere with the intention of people watching it e.g. a school? Might be best to get one with a clear enclosure so people can see into it. Or at least with a camera to stream its progress, in case you don’t want a slightly noisy machine in the workspace.
Is it being placed into a professional setting or hacker/maker space? A lot of newer machines are equipped with sleeker designs to add a professional aesthetic to the workshop environment.

Price
Of course price will be one of the overall deciding factors. Desktop printers range from the hundreds to the thousands. Typically the price of the printer will reflect the quality of the prints it gives. The higher the price the higher quality of the prints. Also the higher the price of maintenance and replacement parts. But 3D printers are popular, this generates a lot of competition between manufacturers. Meaning that prices are likely to go down and the quality shall improve.

Conclusion
Take some time to pick what is right for you. Compare our 3D printers online to make the best choice for you.

https://www.dream3d.co.uk/desktop-3d-printers/compare-desktop-3d-printers/

Basics of Model Design for 3D printing

Fine Details
The smallest feature on a model you can make is double the size of the thread width. The thread width is calculated by finding out the diameter of the 3D printed nozzle. Typically printers have a 0.4mm or 0.5mm nozzle. This meaning that the smallest circle that the printer can draw is the size of two thread widths. E.g. A 0.4mm nozzle produces a 0.8mm circle.
Walls along the X and Y axis should not be thinner than 0.4mm, otherwise nothing will print. Even then the wall will be very unstable. It is only possible to print parts less that 0.4mm on the x axis of high spec printers.

Tolerances
It is advisable to do your own tests to get the optimum fit for interlocking parts.
General approximations:
0.2mm offset for a tight fit, for press fits or connectors
0.4mm offset for loose fits, such as hinges.

Factor in Support Material
Any part of an object which overhangs by more than 45degrees will require support material underneath of it. Support material can damage the outside of your model and is time consuming to remove. Try to design pieces to require as little support as possible. You can split up pieces of a print to be reassembled later on.
Using a lot of support material wastes money as it is removed and binned afterwards. Plus the product will take longer to print. On top of this you will also spend a lot of time cleaning off the support material.
Support also adds extra complexity to a model which results in a higher risk of errors when printing.

Design to Not Use Support Material
Take note of bridges in designs. Imagine you are trying to print the letter H. The middle section stretching between the two edges is the bridge. Typically, if a bridge is under 36mm you will get drooping of 0-0.5mm.
Longer bridges of 36-60 will have drooping of 0.5-2mm.
However these are only rough estimates and depend on you printer, material and print settings.
If you look at bridges in more complicated prints you can factor in the distance apart to try and prevent the need for support material.
Say you were trying to print the letter T, he top of the letter will undoubtedly create errors in the drawing as there is nothing for the material to hold onto. Yet if you changed the orientation of this print, so that the letter was lay down you would no longer have this problem. You don’t always need to make changes to your model to improve the results.

Orientate the Model for Best Resolution
As the prints resolution along the x and y axis are predetermined by the thread width you can only get finer detail along the Z axis. Meaning that finer details should be facing up towards the printer head to be able to print in layers finer than 0.4mm.

Questions to ask yourself
Which side will be seen? Are you making multiples? Will it be easy to clean? Will you be able to remove support?

Fixing Digital Models
Some software might not render your file to a high enough quality. This typically results in tiny holes in the design where parts of the model have not connected together properly. You can also get overlapping walls which can cause problems when it comes to printing.
There is free software on the market which allow you to check and repair your model for errors and holes. Examples of this are, Meshlab, Meshmixer, and Netfabb Basic. These will either check or repair your file for errors or holes in the design.

Stress Areas
Consider adding a chamfer onto the points where different planes meet. For example if you are printing a model of a house, the 90degree angle where the wall and floor meet needs a small chamfer where they meet. This will relieve stress at the point where they join. If dropped this is where they are most likely to break.

How to stop your model warping

Key Points
Keep the bed clean and warm
Level the bed properly
Put your printer in a consistent environment, e.g. no rapid temperature changes.

What is warping
Warping is the result of material shrinking whilst 3D printing. This causes the corners of the print to lift and detach from the build plate.

How does it occur?
Most often, warping appears when a model cools down too quickly while it is still being printed.
Material is heated up to extrude onto the printed bed. When the material is heated it expands and then cools and contracts. If material contracts too much, warping occurs.
Warping is often worse when the parts are made with solid fill and take up a lot of room on the build platform.

Materials most susceptible to warping
PC is more susceptible to warping than PLA
ABS is very susceptible to warping, especially when being used for large models.
Industrial materials such as PC and CPE+ needs an enclosure due to the high printing temperatures required to print them.
PLA is one of the best materials for large prints as it is less susceptible to warping

How to prevent it?
Carefully position your printer. Keep your printer outside the path of direct airflow, such as air-conditioning units or open windows.
Keep the printer doors closed, this makes the printing environment a warm and consistent environment.

Use a heated build plate- this keeps the material at a temperature just below the point where it solidifies. This is known as the, ‘glass transition temperature’. This ensures that the build stays flat and connected to the build plate.
Level the bed, otherwise layers won’t be able to stick to an un-even surface.
Make sure the first layer is firmly attached to the print bed. If the distance between the build plate and the nozzle is to wide, material can become loose easily. If you are having problems getting the first layer right, relevel the bed.
Make sure the bed is smooth and clean. With no oil or grease on it as this will reduce adhesion.
Use a brim this is a single-layer-thick flat area around the model. A brim will resist any upwards pull from corners trying to lift away from the bed.
Use a raft, this is a thick grid between the model and build plate which distributes heat evenly through the model. This is particularly useful when printing something which does not have a flat base.

Adjust initial layer settings, the first layer is the most important to make sure the print sticks to the bed. There are two important printer settings to monitor to do this that influence the initial layer height and initial layer speed. Typically a thicker first layer is more adhesive. As this means that calibrating the build plate is not as critical, but still advisable. It is important to have a slower first layer, this will prevent the head picking up material and dragging it across the build plate. Aim for a first layer with small tight, nearly seamless lines to get a smooth bottom layer.

Ada Lovelace Day

The second Tuesday of every October marks Ada Lovelace Day to celebrate the achievements of women in STEM careers.

Ada Lovelace was an English mathematician and writer. She is known for her work on Charles Babbage’s proposed mechanical general-purpose computer, the Analytical Engine. Lovelace was the first to realise that the machine could be used for more than just calculation. She published the first algorithm intended to be carried out by the machine. As a result she is regarded as the first programmer and as the first to recognise the full potential of a “computing machine.”

Me and Hannah are here doing are part for the ladies of STEM. Keep up the good work everyone else and always remember to keep inspiring young girls to embark on careers in STEM.

Happy Ada Lovelace day everyone!

#AdaLovelaceDay

Dog with 3D-printed skull gives researchers hope

Amazing story.
A dog with a little bump on the head turned out to have a big tumour. Vets recreated his skull using 3D printing technology in order to operate. He is now happy and healthy.
This has given hope to researchers seeking to help human patients.
See the story below

https://www.cbsnews.com/video/dog-with-3d-printed-skull-gives-researches-hope/