Thermwood tests 3D printed carbon fibre-filled PPS panels without coatings

Thermwood has taken a major step toward its goal of 3D printing autoclave capable tooling from high temperature carbon fibre filled thermoplastic materials.

The manufacturing company 3D printed 50% carbon fibre-filled PPS panels on its LSAM additive manufacturing machine, maintaining the part’s vacuum to an industry-standard level, without coatings. Testing of the part was conducted by the Fleet Readiness Center, located at MCAS Cherry Point, NC, under a previously announced Cooperative Research and Development Agreement (CRADA) partnership. The results met FRC-East acceptance criterion that the bag must not lose than more than 2 in Hg over five minutes.

As an added benefit, Thermwood believes it will soon be capable of producing moulds and tooling that function properly under vacuum in a heated, pressurized autoclave, also without the use of any type of coating to seal the printed tools.

Previously, other unaffiliated companies have tested actual tools printed by Thermwood from 20% Carbon Fibre-filled ABS and have also found that those tools held vacuum to an acceptable level without the use of any sealer or coating; however, the ABS material is not suitable for high temperature applications.

Yet, several parts have been made from those tools under vacuum at room temperature and at slightly elevated temperatures. Thermwood has also already printed a 50% Carbon Fibre-filled three dimensional PPS mould which has not yet been tested. Thermwood’s goal is to produce moulds that will be used in a production autoclave, moulding finished parts suitable for actual end use.

Thermwood’s additive printing process differs fundamentally from conventional Fused Deposition Modelling (FDM) printing. Most FDM processes print parts by melting and extruding a relatively small bead of thermoplastic material onto a heated build plating that is contained within a heated chamber. The heated chamber keeps the extruded material from cooling too much before the next layer is added.

Thermwood machines print a large bead at such a high rate that a heated environment is not needed. It is basically an exercise in controlled cooling. Print speed is adjusted so that each layer cools to the proper temperature just as the next layer starts to print resulting in a continuous printing process that produces high quality parts. Thermwood believes this fundamentally different approach produces superior parts.

One other feature that Thermwood engineers believe helps produce solid, void free parts, is a patent pending compression roller that follows directly behind the print nozzle, flattening the bead while fusing it tightly to the previous layer.

Thermwood announces 3D additive machines

DALE, Ind. – After an extensive development program, Thermwood Corporation has announced it is now offering a line of Additive Manufacturing Systems for the production of large to very large reinforced thermoplastic composite parts. Thermwood’s new machine line, called LSAM (pronounced L-Sam, short for Large Scale Additive Manufacturing), uses a two-step, near-net-shape production process.

Two-Step Near Net-Shape Production Process

First the part is 3D printed, layer by layer, to slightly larger than the final size, then it is trimmed to its exact final size and shape using a CNC router. The process operates in free space and does not require molds or tooling. 
Next, the LSAM part is trimmed to the exact final size using a CNC router
Thermwood’s target market for this new equipment is the production of tooling, masters, molds, fixtures, patterns and plugs for a variety of industries including aerospace, automotive, boating, foundry and thermoforming. In addition, Thermwood believes it will find additional applications as various industries become aware of the substantial benefits of large part additive manufacturing. For tooling, the primary benefits of this approach are a substantially lower cost and a dramatically shorter build cycle. 

Print and Trim on the Same Machine

Thermwood’s high wall, overhead gantry LSAM machines feature a ten foot wide, five foot high work envelope. Length of the work envelope can be as short as ten foot but as long as 100 foot or more. Machines include both a print gantry and a second trim gantry which is actually a five axis CNC router. Both gantries operate over the entire table surface. With this configuration, all functions needed to make parts are performed on the same machine. 
Thermwood’s print gantry features an advanced, Thermwood-developed, vertically-mounted PH Series print head that melts and precisely meters the polymer bead. It can process filled thermoplastic composite materials at temperatures up to 650 o F. Advantages of this unique triple servo design include a much more accurate print bead, the ability to change bead dimensions while printing, the ability to print at high output rates, better fusion between printed layers and a superior void free printed structure. 

Highest Output Rate Head Available

Thermwood currently offers the PH15 Print Head on it LSAM machines. The PH15 prints at rates up to 150 lbs/hr, which Thermwood believes is the highest output rate available today. Although Thermwood believes the PH15 is appropriate for many current tooling applications, they are actively developing even higher output versions of the PH Series Print Head.
The size and typical geometry of parts to be printed, the number of part to be printed at the same time and the overall size of the machine will dictate how large a print head is appropriate. PH Series Print Heads include the ancillary systems required to dry and transport material from storage to the print head. 
The trim or subtractive gantry is a five axis CNC router system equipped with a 12HP (3,000 to 24,000 RPM) Automatic Tool Change Spindle and a ten position automatic tool changer. The vertical Z axis stroke is enhanced, so that the router head can machine from the print table surface to a point completely over the top of a printed part. The machine is also equipped with an automatic tool length measurement system and Thermwood’s patented impact resistant head. The machine uses Siemens Intelligent Servo Drives throughout, for both printing and trimming. 
Each gantry has its own, free standing Thermwood high performance Q-Core CNC Control for movement. The print gantry also includes an integrated print head control to manage melt, pressure and metering functions. Special control functions, not normally part of a CNC control, have been developed to operate the servo drive print head and bead compression wheel. These functions automatically perform tasks that would otherwise need to be incorporated in the CNC print program. This simplifies 3D print programming. 

Exciting New Manufacturing Revolution

“This is exciting”, says Thermwood’s founder and CEO, Ken Susnjara. “We are at the beginning of what appears to be a revolution in manufacturing and we look forward to the new challenges and incredible possibilities that this type of transformational change brings”.