About 3D printing
What is 3D printing?
3D printing is also known as rapid prototyping fabrication or additive manufacturing, it is a low volume production and prototyping process whereby a real object is created from a 3D design. The digital 3D-model is saved in STL format and then sent to a 3D printer. The 3D printer then print the design layer by layer and form a real object.
What is a 3D printable design or model?
Designs or models are 3D printable when they can be sent directly to a 3D printer. A 3D printer needs files in the industry standard file format STL. Most 3D design software can export to STL. 3D printable designs must be watertight, meaning that the design has only closed solids, and no open surfaces. All planes must have an internal and external thickenss.
What can you make with 3D printing?
In 3D printing area, people say "If You Can Draw It, You Can Make It". Many items can be made with a 3D printer. However complicated objects can only be made by professional 3D printers, they are not yet affortable for common family.
What 3D Printers aren't?
3D printers do not:
- Print 3D images (like on 3D TVs) on paper, brochures or name cards; 3D printers create real tangible objects out of real materials
- Magically transform photos into sculptures; objects must first be design or draw in CAD software, then exported to STL before they can be printed
- Substitute traditional manufacturing methods; 3D printers are used to prototype and make limited productions of a new design
What are the materials used to print 3D objects?
Many different materials can be used for 3D printing, such as ABS plastic, PLA, Selective Laser Sintering (SLS) materials such as polymides and other sintering powders, stereolithography (SLA) materials such as Acrylic resins and photopolymers wax.
At Maxxeshop, we are able to fabricate 3D objects with ABS, PLA, Flexible rubber-like plastic, dissolvable plastic such as HIPS and PVA, and unique to Inventadore only - SLS polymides composite materials such as PA12 & 11 nylons, ABS and glass or carbon fibre composites and alumide.
Interested to fabricate your 3D objects in metal? Talk to us and let us help you to realise your idea in metal 3D object.
What are ABS and PLA?
ABS (Acrylonitrile Butadiene Styrene) is a common thermoplastic well known in the injection molding industry. It is used for applications such as LEGO, electronic housings and automotive bumper parts.
PLA (Polylactic Acid) is a biodegradable (under the correct conditions) thermoplastic derived from renewable resources such as corn starch or sugarcane. It is one of the most popular bioplastics, used for many applications ranging from plastic cups to medical implants.
- ABS, ASA and PLA can be used to create dimensionally accurate parts, printing details down to 0.8mm and minimum features down to 1.2mm. For connecting or interlocking parts, a tolerance of 0.5mm is recommended and using a minimum wall thickness of 1 - 2 mm will ensure adequate strength in wall elements.
- Due to its lower printing temperature, PLA, when properly cooled, is less likely to warp (making it easier to print with) and can print sharper corners and features compared to ABS.
- With similar tensile strengths, ABS and PLA are both adequate for many prototyping applications. ABS and ASA are often preferred due to its improved ductility over PLA. With a higher flexural strength and better elongation before breaking, 3D printed ABS can be employed for end use applications whereas PLA remains popular for rapid prototyping when form is more critical than function.
- For high temperature applications, ABS or ASA (glass transition temperature of 105°C) is more suitable than PLA (glass transition temperature of 60°C). PLA can rapidly lose its structural integrity and can begin to droop and deform, particularly if under load, as it approaches 60°C.
- PLA is stable in general atmospheric conditions and will biodegrade within 50 days in industrial composters and 48 months in water. ABS and ASA iare not biodegradable, however it is recyclable. PLA is regularly used for the production of food related items.
How long does a 3D print take?
It depends on the size and complexity of the print, and also on your chosen layer height. A finer, higher resolution print will take much longer, but will look very much smoother.
How much will it cost to print?
This is a very common question, however is it impossible to provide you with an answer remotely close to the actual price you would pay to print your part.
Unlike other 3D printing service centers we charge by amount of material consumed, and not by the outer dimensions of the object, as such objects of the same size may have different prices due to their geometry or shape.
To illustrate the complexity of quoting a price without seeing the corresponding STL file, lets consider three 10cm cubes:
- a solid block;
- a hollow box with 5mm walls, and
- a wireframe with 5x5mm vertices.
Although these three cubes have the identical outer dimensions, they differ completely on every other aspects, as shown in this table.
|Effective Volume||Weight Consumed||Support Material Consumed||Time|
|Solid Block||1000 ㎤||1999 g||35 g||22:45 h|
|Hollow Box||271 ㎤||560 g||48 g||22:45 h|
|Wireframe||28 ㎤||153 g||239 g||22:45 h|
Which comes down to a 600% price difference between the Solid Block and the Wire Frame cubes.
For objects other than cubes, the price difference is also highly correlated with the quality and capabilities of a 3D modeler, and his or her abilities to design for a specific manufacturing technology.
As design rules are different for each 3D printing or manufacturing technologies, printing something that is designed for one technology while using another might be possible, or might be super expensive.
About fragile and delicate parts
Designs often require the inclusion of fine, delicate and fragile features; features which push the limit of today's 3D printing technology.
We fully understand the need for these features and do our best to ensure they are printed successfully and accurately.
Whenever possible we will identify such fragile and delicate features and provide you with advice and assistance on how to modify your design for a successful print.
However, if you do choose to print parts which we feel are too fragile and delicate, we cannot be held liable for them breaking as we manipulate the parts post-print. In which case the client remains responsible for the cost of printing these parts.
Alternatively, we can deliver you as-out-of-the-printer parts, to which support material remains attached.
Varying the material density will effectively reduce costs of a 3D print. It is to note that varying a models' material density will significantly impact its mechanical properties.
Cost saving through material density variations in FDM 3D prints can be achieved by varying the width of the internal honeycomb scaffolding structure, which will in turn drastically reduces the printing time. The images below show possible honeycomb widths.
In both cases, the shape or external appearance of a model is unaffected.
Our printers feature selectable print resolution choices for a balance of speed and quality, from Ultra-High definition 50 micron layers (about the thickness of a piece of normal printer paper), a middle 100 micron layer, a large 200 micron layer and a larger 300 micron layer setting where speed and turnaround is the biggest priority.
Designing for 3D printing
To successfully 3D print your design please take the following considerations into account:
- Design to scale. Design using real world measurements: to the size, specifications and orientations your design should be 3D printed.
- Consider printer resolution. To ensure a successful 3D print, design the smallest feature to be no less than twice the printers' resolution.
- Designing moving parts. When designing assemblies with moving parts, provide an allowance of at least 100 microns between any contacting surfaces.
- Design single solids. Designs composed of multiple stacked and juxtaposed solids will 3D print as multiple stacked and juxtaposed solids instead of forming a single unified solid. Before exporting your design to STL, ensure that all stacked or juxtaposed solids are merged into a single solid.
- Design closed/watertight objects. Designs with surface gaps cannot be 3D printed. After exporting your design to STL, use Netfabb to ensure that your designs' surfaces are both closed and oriented. If they are not, use the repair functions to close and orient them.
3D printers have a few mechanical limitations preventing them from creating certain geometries, as such certain considerations must be taken into account during the design process.
- Floating Surfaces
For the same reasons, floating surfaces are particularly difficult to print, these include structures such as the bar in the letter 'H' or the arch in the letters 'D', 'O' or 'Q'. We recommend designing floating surfaces using parabolic or pyramidal scaffolds.
- Unbalanced structures
For the same reasons, unbalanced structures are particularly difficult to print as they often keel over under the weight, as such we recommend designing parts for their centre of gravity to be above their base.
- Small Details
All FDM 3D printers over-extrude slightly during sharp direction change, as such small details such as holes and saw teeth or points tend to not be as sharp as the design prescribes. These defects can either be fixed by filing or sanding the over extrusion or by designing larger features and by using rounded corners, which effectively dampens the speed of the direction change.
- Plan for the print
We recommend designing your part following two simple rules:
(1) the base of the part should be no less than 80% of the largest area and
(2) orient the part so that all its features point upwards (as opposed to downwards or sideways).
We prefer, and recommend, designing with Siemens Solid Edge, Autodesk Inventor or Solidworks, however if commercial software is not an option, there are excellent free software you can use to do 3D modelling:
- SketchUp. A suite of applications for professional design, visualisation and communication.
- Blender. Blender is the open source, cross platform suite of tools for 3D creation.
- Autodesk Fusion 360. A powerful, yet simple 3D creation and editing tool which supports many 3D printers.