The Secret to LSAM Print Quality… A Different Process

Prior to LSAM, 3D polymer printing was all done using essentially the same approach. Parts were printed with a small print bead onto a hot table, in a heated chamber, keeping the printed part hot until printing was complete.

While this worked reasonably well for smaller net shape parts, scaling the process up for large near-net-shape parts didn’t work quite as well.

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A Different Approach

Thermwood took a fundamentally different approach with our LSAM large scale additive manufacturing system. Instead of printing with a small bead in a heated environment, Thermwood uses a large bead, printed at room temperature in an essentially “continuous cooling” process.

The beads are large enough, with enough heat energy, to completely fuse with the previous layer. Thermwood also employs a temperature controlled “compression wheel” to form the round melt coming from the print nozzle into a flattened bead and fuse it with the previous layer.

With this process, print speed is essentially controlled by the cooling rate of the polymer being printed, rather than by the output of the print head. The printed bead must cool enough to support the next layer, but must still be warm enough to fuse completely with it.

This means that there is a specific temperature range, which is different for each polymer, where this approach to printing works. Each polymer requires a certain amount of time to cool to within that temperature range. That amount of time is the fastest that a layer can be printed, regardless of its size.

The output capacity of the print head simply determines how large a layer you can print in the amount of time available for each layer. Thermwood’s standard 40mm melt core can print layer lap lengths of over 200 ft. with most polymers. For even larger parts, Thermwood is working on an even larger melt core which can be retrofitted into the same print head housing as the 40mm core.

This process yields almost perfectly fused structures. Molds printed using the LSAM process routinely hold vacuum at elevated temperature and pressure in an autoclave without the need for any type of external coating.

Unique Part Hold Down Method

The only issue remaining was how to hold the parts during printing. In the previous process, polymer parts tend to stick to a heated table. Since Thermwood’s process doesn’t have a heated table, this wouldn't work. Also, since parts are both printed and trimmed on the same machine with LSAM, the part needed to be held for trimming after it was printed and cooled. Parts generally release from a heated table when they cool down.

LSAM's Patented "Bead Board"

Thermwood’s approach to this requirement turned out to be quite unique. We developed a “bead board” to hold the parts both during printing and trimming.

The beard board consists of a plywood panel to which ABS pellets or “beads” are glued.

When a part is printed with this method, it fuses with the ABS beads holding it to the board, but one additional thing happens. Heat from the printed bead not only heats the ABS beads but also heats the glue holding them.

The glue softens enough that the beads can move on the board as the part cools and shrinks, eliminating cooling stresses that might otherwise be generated by a more rigid system. Once cool, the glue re-hardens holding the part securely for trimming. A couple of large screwdrivers and a hammer will remove the part once it is complete. 

LSAM Printing - Final Thoughts

This print approach required an almost complete rethinking of the print head design, control system operation and software, and we will explore those issues later.

For now, know that LSAM printing, at its very core, is fundamentally different. 

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More Information on LSAM

LSAM is based on exciting new technology developed from an entirely new direction.

LSAM is intended for industrial production. It is not a lab, evaluation or demonstration machine, but is instead a full-fledged industrial additive manufacturing system intended for the production of large scale components.

Thermwood has already applied for over 45 separate patents on various aspects of this new technology (more than half of which have already been granted) and more will be coming as development continues. LSAM is truly “state of the art” in this exciting new world of Large Scale Additive Manufacturing. 

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Installation of the world's largest composite 3D Printer is now complete at Local Motors. This massive Thermwood LSAM 10'x40' is ready to get to work making the Olli! 

Thermwood LSAM 10'x40' - Ready to work! 

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Looking down the working envelope from the print gantry side of the Thermwood 10'x40' LSAM

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A part in the process of being printed on the Thermwood 10'x40' LSAM at Local Motors

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Looking down the working envelope from the print gantry side

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Another view of the 10'x40' LSAM at Local Motors

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A view from the trim gantry side of the Thermwood LSAM 10'x40' at Local Motors

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About The Thermwood LSAM

Thermwood offers a line of dual gantry additive manufacturing machines which both print and trim parts on the same machine. These are large industrial additive manufacturing machines that can be up to 100 feet long.  

LSAM (pronounced L-sam) represents an all new technology for large scale 3D printing of thermoplastic polymers. While other large scale additive efforts attempt to scale up small, filament-fed desktop printer techniques, LSAM is, at its core, designed for additive manufacturing of large structures using a fundamentally different approach

LSAM is different. The print process is different. The machine is different. The print head is different. The control is different. The software is different and the resulting parts are different.

LSAM is intended for industrial production. It is not a lab, evaluation or demonstration machine, but is instead a full-fledged industrial additive manufacturing system intended for the production of large scale components.

Although suitable for producing a wide variety of components, Thermwood is focusing on producing industrial tooling, masters, patterns, molds and production fixtures for a variety of industries including aerospace, automotive, foundry and boating.       

About Local Motors

Local Motors is a ground mobility company focused on shaping the future for the better. Founded in 2007 with a belief in open collaboration and co-creation, Local Motors is a digital OEM, capable of micro-manufacturing, sales, service and operations all from a local footprint using a microfactory.

Meet Olli

 

 

Birds-eye view of two Thermwood LSAM (Large Scale Additive Manufacturing) machines currently in production here at our factory. Get up close and personal with a 10'x20' as well as a massive 10'x40' LSAM Large Format 3D printer. 

About The Thermwood LSAM

Thermwood offers a line of dual gantry additive manufacturing machines which both print and trim parts on the same machine. These are large industrial additive manufacturing machines that can be up to 100 feet long.  

The Thermwood LSAM is used to produce large to very large sized components from reinforced thermoplastic composite materials. 

Although suitable for producing a wide variety of components, Thermwood is focusing on producing industrial tooling, masters, patterns, molds and production fixtures for a variety of industries including aerospace, automotive, foundry and boating.    

The video below shows the process of creating a 3D printed boat hull pattern (from which fiberglass boat hull molds are made), on a Thermwood LSAM. 

Click for More Information on the process

This achievement was the result of a collaborative effort between Thermwood Corporation,Techmer PM and Marine Concepts.

The tool was printed slightly oversized and then trimmed to final net size and shape using a Thermwood’s large scale additive manufacturing (LSAM®) system.

It was made from Techmer’s Electrafil© ABS LT1 3DP, which has proven ideal for marine tooling applications when processed using LSAM print technology. The entire print, assembly and trim process required less than ten working days to complete. After the printed and trimmed tool was coated and finished, a fiberglass mold was produced using the printed pattern. This effort clearly demonstrates the feasibility, practicality, economics and advantages of using additive manufacturing in the production of boat tooling. 

The final tool was printed in six sections, four major center sections with walls approximately an inch and a half thick and a solid printed transom and bow, which were pinned and bonded together using Lord plural component urethane adhesive before being machined as a single piece on the Thermwood system.

A cooperative effort between Thermwood Corporation, Applied Composite Engineering (ACE), Techmer PM and Purdue University’s Composites Manufacturing and Simulation Center has produced a composite helicopter part using a 3D Printed Polysulfone (PSU) mold.

PSU mold printed and machined on a Thermwood 10'x20' LSAM®

Final Part from mold (oil drip pan for a Chinook Helicopter)

The Details

The mold was printed from Techmer supplied carbon fiber reinforced material and trimmed on Thermwood’s Large Scale Additive Manufacturing (LSAM®) machine. ACE produced a production part from the tool in an autoclave using normal production processes.

Despite the fact that Polysulfone appears to be an ideal material for this application, the participants believe this is the first time PSU has been 3D printed, since it processes at temperatures and requires torque levels above those needed for normal polymer extrusion.  The extruder and print head on Thermwood's LSAM machine has been specially designed for ultra-high temperature, high-torque operation.

3D Printing Mold on Thermwood 10'x20' LSAM®

The part, an oil drip pan for a Chinook Helicopter, was molded in an autoclave at 275^oF and 90 PSI. The printed mold held vacuum without the need for special coatings other than normal mold prep and release. With a Tg (glass transition temperature) of 372^oF the participants believe that this particular PSU formulation may be able to process parts at up to 350^oF which is adequate for about 95% of composite parts processed today. Additional tests will be performed to determine the suitability and durability of this material at this temperature. They also plan to evaluate Polyethersulfone (PES) which processes and operates at even higher temperatures.

The PSU mold and resulting part were displayed at the recent AM2017 Additive Manufacturing Conference in Knoxville.

Comparison vs Traditional Methods

Another interesting aspect of this collaborative effort is that a mold for the same part was built by ACE using traditional methods and the cost and build time was compared to making the same tool using additive manufacturing. The results were stunning.

The Results

Additive manufacturing material cost was 34% less and it required 69% fewer labor hours. Build time for the additive tool was 3 days versus 8 days for the conventional tool. If the part was larger, a support structure would be needed for the conventional tool which would add two days and more labor hours to the conventional process. A larger additive tool would not require a support structure.

The goal of this collaborative effort is to develop materials and processes to efficiently and reliably 3D print production composite tooling, capable of operating at elevated temperatures in an autoclave. These first successful results may indicate that they are very near reaching that goal.

Collaborative partners on this project

Applied Composites Engineering – Composites is their business focusing on aerospace. With nearly thirty years in the industry they have shown core competency rarely found in a company their size. This combination of capability and experience provides their customers with the benefits of a larger company supporting more sophisticated projects and larger production along with the speed and flexibility of a smaller enterprise.  

Purdue’s Composites Manufacturing and Simulation Center – Their primary focus among others is to develop a comprehensive set of simulation tools that connect composites from their birth in manufacturing to predicting their useful life. They predict and measure the anisotropic deformation that occurs in printed elements, including a description of anisotropic element shape change during deposition in order to anticipate performance of the printed element.

Thermwood Corporation – Pioneer in CNC development, first company to build and sell a CNC router has moved aggressively into developing and building large scale additive manufacturing systems and industry leading software. Its LSAM (L-Sam) system prints and trims large to very large molds and tools that are solid, virtually void free and able to sustain vacuum without secondary coatings.

Techmer PM - A leading manufacturer of high-performance custom compounds used in the plastics industry, they seek to deliver value-added, breakthrough solutions to the OEM and processing communities worldwide. Working extensively with the additive manufacturing community they have developed materials ideally suited to the additive manufacturing process and have wide-ranging experience with additive manufacturing technology.

A 3D printed boat hull pattern, from which fiberglass boat hull molds are made, has been completed using a near net shape additive manufacturing process and then successfully used to produce a production capable fiberglass mold in a proof of concept joint evaluation program. The completed pattern was recently displayed at the AM2017 Additive Manufacturing Conference in Knoxville, Tennessee. 

Video 

 

 

Finished boat hull pattern - shown with Thermwood LSAM® 10'x20' machine

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A Collaborative Effort

This achievement was the result of a collaborative effort between Thermwood Corporation,Techmer PM and Marine Concepts. The tool was printed slightly oversized and then trimmed to final net size and shape using a Thermwood’s large scale additive manufacturing (LSAM®) system.

It was made from Techmer’s Electrafil© ABS LT1 3DP, which has proven ideal for marine tooling applications when processed using LSAM print technology. The entire print, assembly and trim process required less than ten working days to complete. After the printed and trimmed tool was coated and finished, a fiberglass mold was produced using the printed pattern. This effort clearly demonstrates the feasibility, practicality, economics and advantages of using additive manufacturing in the production of boat tooling. 

The Details

Thermwood LSAM® 10'x20' machine printing two of the six sections

The final tool was printed in six sections, four major center sections with walls approximately an inch and a half thick and a solid printed transom and bow, which were pinned and bonded together using Lord plural component urethane adhesive before being machined as a single piece on the Thermwood system.

Bonding the boat hull pattern pieces together

Bringing the two sections together

Boat hull pattern after bonding together and before machining

Thermwood LSAM® 10'x20' machining boat hull pattern

The final trimmed pattern weighs approximately three thousand pounds. It required approximately thirty hours to print and fifty hours to machine.

Final trimmed pattern before coating

Thermwood’s demonstration machine, used for this program, has a 10 foot by 20 foot worktable and features both print and trim capability on the same machine. The print head used for this project can print at rates approaching 200 pounds an hour when running this particular Techmer material. Thermwood also offers larger machines and higher throughput print heads as part of its LSAM product line. 

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Pulling the Mold

 

Building frame on boat hull pattern to pull mold

Finished frame on boat hull pattern after casting the fiberglass mold

Removing fiberglass mold from boat hull pattern

Finished boat hull mold in red

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Additive Manufacturing Could Change Marine Tooling Process

Additive manufacturing offers the promise of even more advances in marine tooling such as printing the hull and deck pattern as a single piece, allowing a production mold to be taken from the hull and then flipping the pattern over and taking a deck mold from the other side of the same pattern. All of these possibilities result in dramatically lower tooling cost and substantially faster build time. 

For large boats and yachts, Thermwood is evaluating the feasibility of printing molds directly, rather than printing a pattern from which the mold is taken. Because of their large size, these tools will need to be printed and machined in sections, even with very large LSAM® printers. It may also be possible to print integrated cooling channels for air or liquid into these large tools as part of the print process. 

With this initial success and some radical new ideas that appear to be possible with current materials and technology, it is becoming apparent that additive manufacturing may very well represent a disruptive force for the marine tooling industry.

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

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

50% Carbon Fiber filled PPS Panels Tested by Fleet Readiness Center

50% Carbon Fiber Filled PPS Panel Printed and Machined on LSAM

Working toward this goal, Thermwood engineers have printed 50% Carbon Fiber filled PPS panels on its LSAM additive manufacturing machine that held vacuum to an industry acceptable level in independent testing. The test was conducted by the Fleet Readiness Center, FRC-East, located at MCAS Cherry Point, NC under a previously announced Cooperative Research and Development Agreement (CRADA) partnership, and the results met FRC-East acceptance criterion that the bag must not lose more than 2 in Hg over 5 minutes.  

View of LSAM PPS Sample with Vacuum Bag

View of LSAM PPS Sample and Vacuum Bag without Vacuum Hose 

Previously, other unaffiliated companies have tested actual tools printed by Thermwood from 20% Carbon Fiber 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. 

LSAM ABS Demonstration Part showing as printed (rough cut and finished surfaces) 

Vacuum Bagging Test on LSAM ABS Demonstration Part at Fleet Readiness 

Despite that, 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 Fiber filled three dimensional PPS mold which has not yet been tested. Thermwood’s goal is to produce molds that will be used in a production autoclave, molding finished parts suitable for actual end use. 

Thermwood's Additive Printing Process 

Thermwood’s additive printing process differs fundamentally from conventional Fused Deposition Modeling (FDM) printing. Most FDM processes print parts by melting and extruding a relatively small bead of thermoplastic material onto a heated build platin 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. 

Thermwood's Patent Pending Compression Roller 

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. 

More About LSAM

Thermwood’s large scale dual gantry LSAM machines both print and trim parts on the same machine. They are programmed with Thermwood’s LSAM Print ^3D slicing software, which is rapidly becoming the most capable additive manufacturing software in the industry.

The LSAM and its software operate within Mastercam and are specifically designed for near-net-shape, rather than net-shape printing.

It works with most major CAD file formats including virtually all solid, surface and mesh formats. Thermwood maintains a continuing software development effort to continuously improve, enhance and expand its features and capabilities.

New Print Head Design for LSAM

Thermwood Corporation has unveiled a new design for the print head on its large scale additive manufacturing machines which it calls LSAM, (pronounced L-Sam). This new “Universal” design print head can be equipped with any of three interchangeable “Melt Cores”.

The print head is large by industry standards, being over 10 feet long and weighing one and a half tons, but despite the size and weight it moves at speeds up to five feet per second. The print head is designed so that the “Melt Core”, which consists of a feed housing, extruder and polymer melt pump, can be changed should higher or lower print rates be required.

Universal Print Head Installed on LSAM Development Machine

Thermwood has installed a universal print head on its current 10’ x 10’ LSAM development machine with a 40mm Melt Core and has successfully printed composite tooling masters from 20% Carbon Fiber filled ABS, and has printed actual autoclave tooling from both 50% Carbon fiber filled PPS and 20% Carbon Fiber filled Ultem using this print head. 

LSAM is DIfferent Than Other Thermoplastic 3D Printers

The print head is a critical element in Thermwood’s additive manufacturing process which functions differently than other FDM thermoplastic 3D printers. Most thermoplastic additive manufacturing systems print with a relatively small print bead onto a heated table in a heated environment. The heated environment is needed to keep newly printed layers from getting too cool to properly fuse with subsequent layers.

In Thermwood’s approach, the only heat source is the print head itself. A heated environment isn’t required. The process prints a large bead at such high output rates that the printed layer must be cooled rather than heated to achieve the proper layer to layer fusing temperature. The entire process is essentially an exercise in controlled cooling and produces large size, high quality, virtually void free printed structures.

Each layer is printed at a rate that allows it to cool to the ideal temperature before the next layer is applied. If the layer becomes too hot, print speed is reduced to allow more cooling time. If it becomes too cool, print speed is increased to reduce cooling time. 

Real-Time Thermographic Image Display

A built-in thermographic imaging system displays a real time thermal image on the CNC control screen which aides the operator in achieving and maintaining the ideal print temperature during the print process.

Temperature Control Module Integrated into LSAM

The LSAM Universal Print Head can process material at temperatures up to 450^oC. It uses an electronic temperature control module integrated within the print gantry CNC control, allowing full integration of temperature and pressure control with exclusive features of Thermwood’s print gantry CNC control, better supporting processes unique to 3D printing.

Three Melt Core Choices for LSAM

Thermwood offers three melt cores for its print head, each with a different maximum print rate. The maximum print rate determines the longest bead that can be printed during the available cooling time between layers.  This cooling time varies depending on material, amount of fan cooling and geometric shape of the layer, but the faster the print rate the more material that can be laid down within the cooling time between layers, so faster print heads allow larger parts to be printed, but don’t really print parts faster.

Fastest Printing With LSAM

Even the standard 40mm LSAM melt core is generally so fast that it must be slowed on most parts to keep from printing a layer so fast that it doesn’t have sufficient time to cool properly between layers. In this case, often multiple parts can be printed in the same time it takes to print just one.

The LSAM machine is equipped with a standard 40mm Melt Core which includes a patented 40mm high speed extrusion screw coupled to a corresponding melt pump and deposition head. This standard configuration processes over 200 pounds of material an hour, depending on the specific material and is suitable for parts that have a print layer lap length of up to 200 feet while printing a standard bead that is .200 inch thick and .830 inch wide. This configuration has proven more than adequate for virtually all large parts today.

If even longer layer bead lengths are required, higher output Melt Cores are available. A 60mm Melt Core can process 50% more and a 70mm Melt Core has operated at rates of over 500 pounds per hour, which Thermwood expects to increase.

The fastest speed at which a part can be printed is determined by the cooling time required to reach the proper bonding temperature between layers and not by the output of the print head. Larger print head outputs simply allow larger parts to be printed within the cooling time between layers.

High output melt cores do, however, have a minimum operating speed so may not be suitable for smaller parts. If both small and really large parts are required on the same machine, the melt core can be changed from one size to another in less than a shift. 

New 10'x20' Demonstration LSAM Under Construction

This print head will be installed on a new 10’ x 20’ demonstration machine currently under construction at Thermwood. Production machines come standard with the 40mm Melt Core.

Thermwood’s LSAM machines both print and trim on the same machine using separate gantries. The new approach to print head design adds even more flexibility.

LSAM Produces Solid, Void-free Parts

Using this technology, Thermwood has been able to produce large tools that are solid and void free enough to maintain vacuum without sealing or surface coating. This simplifies production of the tool, allowing accurate machining of the surface without having to deal with distortions that might be caused by variations in the thickness of a coating. 

Print and Trim on the Same Machine

Thermwood offers a line of dual gantry additive manufacturing machines which both print and trim parts on the same machine. These machines can be up to 100 feet long with print head output rates from 150 to 500 pounds per hour.  

The Thermwood LSAM is used to produce large to very large sized components from reinforced thermoplastic composite materials.

Although suitable for producing a wide variety of components, Thermwood is focusing on producing industrial tooling, masters, patterns, molds and production fixtures for a variety of industries including aerospace, automotive, foundry and boating.   

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Thermwood PH50 Head Successfully Tested

After recently announcing our line of LSAM (large scale additive manufacturing) machines, Thermwood has now built and tested a high output version of our PH Series composite thermoplastic 3D print head.

At a print rate of 500 lbs/Hr, our newest and largest print head, the PH50 is more than three times faster than even our current PH15 print head (which we believe is currently the highest output composite thermoplastic print head available).  

The Thermwood-designed PH series print head uses three servo drives in a unique configuration.

The advantages of this new design include:

• a highly accurate print bead, the ability to change bead size while printing
• high output print rates
• better fusion between printed layers
• a virtually void-free printed structure

Thermwood has been operating the PH15 print head on the development version of our large scale additive manufacturing machine, called LSAM (L-Sam). The PH15 features a maximum print output rate of 150 Lbs/Hr when running a 20% carbon fiber filled ABS material. Our newest, and largest print head, the PH50, has been successfully bench-tested at a print rate of slightly over 500 Lbs/Hr running the same material.

A New Way to 3D Print

Fast print rates make possible all new ways to 3D print. The maximum print rate on a particular part is dictated not by the output of the print head, but instead, by cooling. When a layer is printed it must be allowed to cool sufficiently to stiffen enough to support the next layer but should not be allowed to cool so much that it doesn’t fuse properly with the next layer. This means that, although you may be able to print much faster, with most materials, you must wait at least 1 ½ to 2 minutes before you can print another layer. This would tend to make high output print heads unnecessary except for really large parts, but there are situations where this is not the case. 

At times, parts are printed as completely solid structures. When this occurs, bead length adds up quickly. A 5 foot by 5 foot solid layer requires 375 feet of bead length with a 0.800” bead width. Even with a 125 foot per minute print speed (which is the print speed of the PH50 at full output), it will require at least three minutes to print that layer. While this is still within a good layer to layer working time, it is clearly not overly fast. 

Some parts which are printed vertically are so long that they must be printed in multiple sections which are then bonded together. With a fast enough print head and large enough table, all sections can be printed at one time rather than printing them one at a time. In this approach, you print a layer on one part, then move to the next and the next, until you have printed that layer on all the parts. Then, you return to the first part which should then be ready for another layer. You can also mix different types of parts and print them all at the same time, rather than one at a time.  With additive manufacturing technology today, this is the only way to speed up production rate. This approach makes fast print heads and large table sizes not only practical but quite desirable. 

Thermwood's PH Series Print Head Design

Thermwood’s PH Series print head design uses a servo-controlled plastic extruder with a specially designed, patented plasticating screw to heat and soften the composite thermoplastic material. It then uses a servo-controlled fixed displacement polymer pump to deliver the softened material at a precisely controlled rate to the print nozzle. This dual-servo, two-step approach to generating the print bead eliminates a variety of problems encountered when trying to use just an extruder to print and generates a highly controlled material flow rate which results in a highly accurate and controllable print bead size. 

Thermwood’s PH Series system generates a relatively large print bead, applied at high speed. The print head is slaved to machine speed so as the machine speeds up and slows down, the output of the print head automatically adjusts to keep the size of the print bead consistent and accurate. This print speed control is automatic and doesn’t need to be incorporated into the CNC print program, greatly simplifying programming. An additional feature of this approach is that the print program can vary the size of the print bead during printing, something Thermwood has found to be a valuable capability. 

Once the bead has been applied, the PH Series print head uses a unique servo-controlled compression wheel to flatten and fuse each new print layer to previous layers. This wheel is the third servo in the PH series print head and can be instructed to automatically track machine motion. 

Since it tends to squeeze out any air that might otherwise be trapped between layers during printing, Thermwood has found that this compression wheel results in superior bonding between printed layers and a virtually void free printed structure. 

Another Unique Feature

A unique aspect of this new print head design is that, unlike machine motion, the three servo drives in the print head are not machine axes. Thermwood’s print gantries have six servo drive systems, but only three of them are axes. A machine axis needs to be programmed. The servo drives in the print head have their own unique, independent, self-operating intelligent control functions, which they continuously perform without specific ongoing CNC program commands.

The CNC program simply tells them to perform their function and they do it without further specific instructions, even if those functions require them to interact with the machine program, machine motion or each other. For example, simply turn on the print function and move the machine and the print head will print the proper size bead as the machine moves, automatically adjusting for acceleration, deceleration and different machine speeds. Engage the compression wheel and it follows machine motion automatically. During printing, a delicate balance exists between the extruder and polymer pump in the print head. Achieving and maintaining this balance during all aspects of operation is also automatic. 

PH50 Successfully Operated at Full Output

Currently, the new PH50 print head has successfully operated at full output in a static position. Thermwood is replacing its 10x10 foot LSAM development machine with a 10'x20' foot demonstration machine to verify and demonstrate operation of this new head at full print speed. Thermwood believes that 10'x20' is as small a machine as is practical for this high output print head. LSAM machines are available with table lengths of up to 100 foot or more. Thermwood is confident that technology in the PH Series print heads could be used in even higher output print heads should a need ever develop.  

For More Information

The Thermwood line of LSAM machines are available now, and you can get more information and see videos of these new heads in operation here

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Thermwood LSAM Now Available 

After an extensive development program, Thermwood Corporation, (Dale, Indiana, USA), 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.  

 
  

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”. 

 

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