The Support System of 3D Printing
'So a 3D Printer can print a part in the air, right?', asked a client.
'Practically not, but you are close.' We replied.
3D Printing refers to processes used to create a three-dimensional object in which layers of material are formed under computer control to create an object. An object is built from an computer aided design (CAD) model file by successively adding material layer by layer.
Now, whether an object requires a support while 3D Printing or not depends a whole lot on its geometry, complexity and the 3D Printing technology being used for production.
Picture: Supports for an object printed in resin.
Supports are required for printers using resin materials for Stereo lithography (SLA) and Digital Light Processing (DLP) Technologies. These support structures look like thin trusses and have a very small contact point with the actual object. These supports usually hang upside down holding the object onto the build-platform.
Picture: Support remains of an object printed in Thermo-plastic.
For an object being 3D Printed using Fused Deposition Modeling (FDM) Technology, a support is required for any inclination in the geometry of an object beyond 45 ° . This allows a print to expand beyond its previous layer's width. Without a support, the layer will hang loose (Commonly termed as over-hangs). The amount of support required for an object impacts the coat of material and post processing time.
The supports leave what are called 'Support Marks' on the 3D Printed objects which have to be sanded/post-processed.
Designing a part keeping in mind its printing orientation is crucial for a successful print. Designing a part so as to reduce overhangs and support material required reduces the cost of the final object as well as time taken to get the finished product. For larger parts requiring excessive support, ideally splitting the object into multiple parts and assembling it saves on cost and improves overall finish quality. A parting line becomes visible for those objects printed in parts and assembled. Paint post-processing can hide such parting lines.
Selective Laser Sintering (SLS) technology and Binder Jetting Technology does not require support structures since it is built within a powdered bed of material.
Direct Metal Laser Sintering (DMLS) technology always uses supports to adhere the object to the build platform during the printing process.