Fused Deposition Modelling (FDM)
FDM is a great technology for producing quick turnaround prints. It is used extensively in the studios as it offers a large range of material options. Low Cost FDM is often used for initial prototyping before a higher quality print is produced either on our industrial scale FDM machines (Fortus) or using another 3D Printing technology such as Selective Laser Sintering or Polyjet. The maximum build size using FDM technology is 914 x 610 x 914 mm, however, due to the high accuracy and limited warping of the parts produced using FDM, multiple parts can be bonded together to produce extremely large parts.
Medium / Commercial Quality Plastic – For this offering we use our high end Stratasys and Fortus equipment. The parts provided are of the highest quality available from FDM printing today
- ABS M-30- Engineered for 3D printing with FDM Technology, ABS-M30 is ideal for concept models and moderate requirement parts including functional prototypes, jigs, fixtures, manufacturing tooling and production parts.
- ABS ESD7 – For applications where a static charge could damage components, impair performance, or cause an explosion, FDM Technology offers ABS-ESD7 static-dissipative thermoplastic.
- Engineers and designers can use FDM parts confidently to create jigs and fixtures for assembling electronic components. Functional prototypes for fuel storage and delivery products also benefit from static dissipation.
- ASA – UV-Stable Prototyping
- ASA is a production-grade thermoplastic that works beautifully with FDM Technology. Available in 10 fade-resistant colours, ASA combines mechanical strength and UV stability with the best part aesthetics FDM technology has to offer. Build enduring prototypes to test fit, form and function – or produce practical production parts for outdoor use. From electrical housings and brackets to sporting goods and automotive prototypes, ASA will give your designs a place in the sun.
A plastic filament is unwound from a coil and supplies material to a heated extrusion nozzle, much like a hot glue gun.
This nozzle is computer controlled and moves the extruder around line by line, layer by layer to build up a completed 3D print.
FDM printing is currently the most economical printing method, however produces parts with visible layer lines and limited resolution. For higher resolution printing, SLS or Polyjet is recommended.’
Q: What are the best applications for FDM and what materials can it use?
A: Fused Deposition Modeling (FDM), a form of rapid prototyping or 3D printing, builds parts layer-by-layer with engineering-grade thermoplastics. It can build almost anything you want; complex geometries and functional parts, including prototypes, low-volume production pieces, and manufacturing aids such as jigs and fixtures.
FDM thermoplastics range from general purpose materials for prototyping and end-use production to high-performance materials for medical and aerospace applications. General-purpose thermoplastics, such as ABS, ABSi, ASA, Nylon 12, and poly carbonate, have good strength and exhibit high tensile and impact properties. These general purpose thermoplastics have been further enhanced to create specialty materials. Advanced FDM thermoplastics include ABS-ESD7, a conductive material which prevents static buildup; C-ISO, a poly carbonate with bio compatible properties and certifications; and ABS-M30i, a material engineered for the food and pharmaceutical packaging industries. For aerospace applications, flame retardant and chemically resistant ULTEM 9085 has been developed to work with FDM.
Q: Do shrinkage and warping present problems with FDM parts?
A: Some FDM machines add shrink rates to parts when they are made, so shrink factors do not have to be designed in. Users can also adjust the shrink values to fit specific geometries when large production runs of similar part designs are needed. FDM systems add small amounts of molten material in a heated environment, so warping is not a common problem. However, to avoid potential warping when building thin-walled sections of a model, such as deformation of vertical walls, designers might add ribs to the walls. This is similar what would be done with standard injection moulded parts.
Ensure a minimum wall thickness of 1mm at least for reliable prints.
Q: Can engineers design FDM parts with threads?
A: Yes they can, but there are several caveats. When designing built-in threads, avoid sharp edges and include a radius on the root. Creating ACME threads with rounded roots and crests works well with FDM. Users should ensure parts have “dog point” heads of at least 0.8 mm to make starting the threads much easier. FDM should not be used to make small threads and cannot make holes or posts smaller than 1.6 mm in diameter. An easy alternative is to use a tap or die to thread holes or posts.
Q: What is the maximum size limitation on FDM parts? And does it matter how parts are oriented during FDM construction?
A: 3D Printing Studios FDM parts can be as large as 914 x 610 x 914 mm.
Designers should note that extruded plastic is strongest in the tensile mode along the X-Y plane. Layers are held together by newly deposited material across the strands (one strand cools while the other is laid on top of it), so the finished part’s lowest strength is in the Z-direction for both tensile and shear modes. Overhanging non-supported features, such as the top of a closed box, require that support material be built, which increases the time and material needed to build a part. Therefore, orientation is usually determined by the part processor. For example, half of a box-shaped casing is built with the main exterior facing down so no internal support is needed.
Q: Can all of an assembly’s parts be made at one time on an FDM machine?
A: Yes but we need to ensure enough clearance between parts to prevent them from fusing together.
Q: Why and how do parts get sectioned?
A: Sectioning is used to: build parts too big for the build chamber by cutting parts into sections; minimise support structures; remove overhanging features from the top of parts (in their build orientation) and build them separately; prevent fragile features from damage during post processing; and to isolate fragile features from a part and build them separately. After fragile features are removed, they can be built in orientations that result in stronger parts.
There are several bonding methods to reattach features and join sectioned parts. Parts may be sectioned prior to manufacturing in CAD, in prototyping software applications or by an FDM service provider.
Q: Can FDM parts be post processed?
A: FDM uses engineering-grade thermoplastics, so parts will withstand a number of post-manufacturing processes. These include machining operations such as drilling and tapping, sawing, turning, and milling. But heat builds up quickly in plastic parts, to avoid distortion, removing material slowly and use coolant. Other post processing operations may include smoothing, burnishing, sealing, joining, bonding, and plating.