Processes

FDM Fused Deposition Modeling

November 30, 2016

Engman-Taylor now provides and has access to all forms of machines, materials, and post processes discussed in this blog. Engman-Taylor will work with you on any of your project needs and will find the best solution via 3D printing. Any questions on 3D printing please contact Jordan Nowak.

Fused deposition modeling, otherwise known as FDM, is one of many 3D printing technologies. This process is what most people most often think of when talking about 3D printing. There is a spool of plastic filament that is inserted into an extruder that heats up the plastic and lays it down layer by layer until a part is eventually built up. That would be the basic definition of this process, when in reality there is much more to FDM than meets the eye. In this blog I will be discussing the following bullet points about FDM.

Benefits of FDM
Machines
Materials
Post processes and finishings

Benefits of FDM

The biggest benefit of FDM technology is the materials that are able to be used with the various machines. Cutting edge materials that are used in everyday manufacturing sites can be used with FDM giving the characteristics and properties that most people are familiar working with. Great quality with exceptional durability and stability gives FDM a leg up on other processes. It doesn’t hurt that this process is also the cheapest way to 3D print, material and machine wise. These printers produce the least amount of material waste (no chemical or toxic fumes involved) and require little to none supervision. Maintenance is minimal on these printers, however if a print head or extruder is jammed it may take some time to fix or replace these parts.

Many manufacturers are using this technology for Jigs and Fixtures, prototypes, injection molding, foam molds, and one off tooling parts, however with the advances in technology they can now use it for low volume production parts, tooling for vacuum forming or molds.

X and Y dimensions will have great accuracy however along the Z axis you will lose some accuracy. This can be altered depending on how you orient your print within the software of the machine. Typical accuracies will be around +/- .0035 in. or +/-.0015 in. per in. whichever is greater. Layer heights can range from 50 microns to 300 microns. The larger the layer the faster the part will print, however surface quality diminishes exponentially. Compared to other processes this is typically one of the slowest depending on the layer thickness and if the part needs support. For a preview of time, it takes 47 hours to print a drone body at 100 microns, longer if you wanted to print at 50 microns. Print beds can also get up to 1 meter x 1 meter x .5 meter, which allow for large 3D prints!

Machines

FDM machines typically go from desktop to design to production level. Desktop printers are your smallest printers for beginners and the production level printers are going to be the ones used for government type projects. Desktop printers can range from $200 to $3,000 whereas production grade machines can range from $50,000 to over $400,000.

Below is a list of quality desktop 3D printers that are great for beginning with especially for the typical hobbyist. This top 10 list was taken from 20 best 3D printers in winter 2016/2017 based on ratings by the consumer.

The next few machines are mid-level to production type machines. They are different and set themselves apart from the typical competition.

Fused deposition modeling has evolved and now there are many different machines that utilize this technology in different ways. Some of my favorite new machines are made by Markforged. This company had started with their Mark One machine and has recently developed their Mark Two and Mark X machines. These FDM printers allow you to intertwine carbon fiber, nylon, fiberglass, high strength high temp fiberglass, or kevlar into your product. This makes very robust tough parts that
durability isn’t even an issue anymore. The machine comes with software that can pause a print to allow you to insert any type of fastener or electronic into your design and then have it print over it to enclose that inserted part into the design. The Mark X does have some nice bells and whistles including a laser scanner to make sure each layer is highly accurate, a camera to be able to watch your print when you are away, and a slightly larger built plate ( 13′ x 9.8′ x 7.87′), however comes at a hefty price tag of $69,000. This is much higher than their Mark two at $12,500 with all the optional upgrades.

Another company that has recently got into the game is 3D platforms. They can boast the largest platform of any FDM machine at 1 meter x 1 meter x .5 meters. This is quite incredible. This printer has a heated bed and dual extruders to be able to print in most FDM plastics and a support material.

3D systems do produce a mid-level FDM machine that is called the Cube Pro. This printer can be equipped with 3 heads to hold 3 different materials that range from elastics to plastics to wood. This is a solid printer that can print detailed parts at 50 microns with an enclosed heated chamber, however extruders and nozzles tend to get clogged very easily. Also you must use 3D systems cartridges that can run you $100 which is $60 more than typical cartridges of filament.

Lastly you have your production grade FDM printers. These printers will come from a company called Stratasys. 3D systems no longer produce production grade FDM printers. The first one we will look at is the Fortus 900 mc. This printer is meant for producing production parts, jigs and fixtures, factory tooling, and functional prototypes. This system contains the largest build plate for production grade machines at 36″ x 24″ x 36″. This build plate is in an enclosed heated build chamber that is contained within the 6,325 lb. machine. While this machine is quite large for typical 3D printers, it holds very large filament containers so that the manufacturer can build highly accurate, quality large parts.

Materials

FDM printers use all different kinds of plastics. Some companies make filaments that are very unique, but can only be used with their printers. Then there are your commercial plastics that can be used on most mid ranged desktop printers. Below most filaments from both commercially and the more popular companies will be described.

The commercial plastics are mainly PLA and ABS plastics. Each cartridge can run from $15-$100 depending on the company.
PLA stands for Polylactic Acid which a biodegradable thermoplastic polyester. Any color can be chosen in PLA. Think of “toy” plastic. Then there are reinforced PLA filaments. Here is a list of materials that PLA can be reinforced with to give the part a certain appearance.

Carbon Fiber
Wood
Glow in the Dark
Copper
Bronze
Silver
Gold
Ferromagnetic

Typically the material properties will change depending on what material the PLA is infused with. Changing the machine parameters is a must, depending on the material (chamber heat, nozzle size, heated plate), otherwise the reinforced PLA will cause jamming of the nozzles and extruders. Wood PLA is made by most companies that produce a 3D printer. This type of filament really does create a wood like part. It can even be sanded and carved like wood. The other very unique type of filament is the magnetic filament that can be used in actuators and sensors and many more magnetic applications.

ABS stands for Acrylonitrile butadiene styrene, which is a much tougher plastic compared to PLA and can take heats up to 80C (176F). This type of plastic can also come in any color and can be reinforced When printing warping can be an issue as the plastic cools the part tends to shrink. It is advised to print in a heated chamber and provide a sidewalk of material to hold the part to the plate to lower the risk of warping.

NYLON is a plastic that starts to get into more of the engineering type plastics. This is a very durable, flexible, high strength material. Has a hardness shore D factor of 75 which is as hard as a hard hat and can be stretched up to 22% before deforming. The tensile strength is 4,785 psi. This plastic can be printed on most mid-level commercial printer, but again needs to have a heated chamber, bed, and sidewalk material to hold the part down while printing. This material works best when printing at 200 micron layer thickness.

PC is Poly-carbonate which is an engineering type plastic. This is a clear filament that is used for high strength and high heat deflection. To print this material you should print above 300C and use a heated bed. This material prints best at 300-400 micron layers for best surface finishes.

Support Material- This material typically will be places on the second or third extruder. Support material allows the print to have overhangs. This material is typically a material that can be dissolved in water or just taken off the part with pliers.

Elastomer Plastic has recently become a new filament that can be used. 3D systems have come up with FLEX an industrial flexible material. This is a filament that when printed can create life like seals, gaskets, baffles, covers and plugs. This material can only work on the cube pro with correct calibration and does have its difficulties while printing. This is a guide on printing with FLEX on the cube pro.

Next will be companies that make materials specifically for their machines.

Markforged

Onyx– This is their new material that is nylon combined with micro-carbon reinforcement. It gives off a beautiful surface finish along with high temperature tolerance.
Fiberglass- This is to be woven in along with Onyx or Nylon, which increases the strength by 500%.

Carbon-Fiber– Woven along with Onyx or Nylon gives the highest strength to weight ratio of all the materials. This will increase the parts strength by 10x while keeping it light as a feather.

Kevlar– Woven in with Onyx or Nylon this will allow your part to be resistant to impacts. Very durable and is one of the most flexible fibers they’ve developed.

HSHT Fiberglass– This continuous fiber can withstand heats up to 150C (302F) along with being very strong.

Stratasys

They do make common materials that are specifically used for their FDM machines. This includes ABS, ABSM30, ABSESD7, ABSi, ABSM30i, ASA, PC, PC-ABS, and PC-ISO.
They have three materials that are high performance level materials and can be used for production parts.

Ultem 1010- Excellent strength, thermal stability, chemical resistance, and the ability to withstand steam autoclaving. This material can withstand temperatures up to 213C (415F) and a tensile strength of 11,700psi! Perfect for aerospace and automotive industries.

Ultem 9085- This is a great strength to weight ratio material that is flame retardant. This is great for the transportation industry because of this and has a great flame, smoke, toxicity rating.

Nylon 12- Is their new material that just came out. This is industrial grade nylon that has the highest elongation before break. Used for snap fits, press fits, high fatigue, and chemically resistant parts.

Post Processes and Finishes

After the part has been taken out of the 3D printer there isn’t much post processing work, unlike most of the other processes. For FDM you will have to remove the sidewalk material (if needed). This can be taken off with your hands or just pliers. Next you will want to take off the support material (if needed). This can be done either by soaking the part in water. Otherwise pliers will work just as well in most cases and the support will come right off the part.

Next depending on the application finishes can be applied. Below are typical finishes that people like to have done.

Hand Sanding
Sealing
Machining to dimensional tolerance
Tumbling
Assembly

Sealing and Assembly in FDM are typically used when the part is too large to fit on the build plate and needs to be divided and printed out in sections. Sealing and assembly is then used to produce much larger parts than what the printer can print at once.

For prototypes and production parts, surface finishes may be applies.

Vapor polishing
Paint
Mold-tec finishes
Decals
Texturizing
Primer
Rubberized paint
Electroplating
Artwork
Dying

More information on our 3D Printing services.

Engman-Taylor company is a highly technical industrial distributor. 3D printing is just one of the many value-add services we provide. Contact us today to learn more.