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.

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. 

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. 

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! 

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

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

Looking down the working envelope from the print gantry side

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

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

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.    

Thermwood Corporation announced today the promotion of Scott Vaal to the position of LSAM Product Manager.

In his new role, Scott will be responsible for all aspects of our Large Scale Additive Manufacturing (LSAM) system including product/software enhancements, potential markets and more. 

Scott is a long-standing employee with Thermwood and has held various positions with the company over the past 24 years.

Scott is married with 3 children and resides in Southern Indiana.

Thermwood Corporation a leading manufacturer of CNC routers and Large Scale Additive Manufacturing systems with thousands of installations worldwide spanning 45+ years of business.

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

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.   

Thermwood Corporation of Dale, Indiana has signed a formal Cooperative Research and Development Agreement with Fleet Readiness Center East located at Marine Corps Air Station Cherry Point, N.C., and part of the Naval Air Systems Command, to conduct a two-year, joint technology development effort centered on Thermwood’s emerging Large Scale Additive Manufacturing (LSAM) technology.

Thermwood’s LSAM machines are large-sized industrial additive manufacturing or three-dimensional printing machines that are available in sizes up to 100 feet long. These systems use a “near-net-shape” approach for making parts in which parts are first 3D printed at high speed to a size slightly larger than needed and then trimmed to final net size and shape. Thermwood’s LSAM machine consolidates printing and machining on the same machine using dual gantries. Dual controls allow print and trim operations to be performed simultaneously, each on different ends of the table.

“We are excited to work with the FRC East and are confident that, working together, we can achieve significant advances and results,” said Thermwood Founder, CEO and Chairman Ken Susnjara. “I am confident that this program will benefit us both while further advancing the state of the art.”

Thermwood has been in a continuous research and development program developing additive manufacturing equipment and technology, and in September announced a line of large scale additive manufacturing systems called LSAM. The dual-gantry, high-wall machines are available in sizes from 10-foot-by-10-foot to 10-foot to more than 100-foot with print capability from 150 to 500 pounds per hour.

 About Thermwood Corporation:

Thermwood Corporation, located in Southern Indiana and established in 1969, offers both three & five axis CNC machining centers ideally suited for the production, fabrication & trimming of wood, plastics, non-ferrous metals, composites and other advanced materials.  Thermwood also offers a Large Scale Additive Manufacturing (LSAM) system for 3D printing reinforced thermoplastic composite materials for producing industrial tooling, molds, patterns, masters, plugs and fixtures for various industries.  Thermwood is deeply involved in CNC and Additive Manufacturing technologies and development, incorporating a high level of smart control technology in its products. 

About Fleet Readiness Center East:

For more than 60 years, the Fleet Readiness Center (FRC) East aboard MCAS Cherry Point, N.C., has played an important part in national defense.  Our workforce has earned a reputation of excellence in providing world-class maintenance, engineering and logistics support for Navy and Marine Corps aviation, as well as other armed services, federal agencies and foreign governments. Our skilled workforce uses state-of-the-art technology to ensure that FRC East is without equal in providing quality, cost-effective support. 

 

About the Thermwood LSAM

 

Thermwood has added thermographic imaging as a standard feature to our large scale additive manufacturing machines (which we call LSAM "L-Sam"). This addition makes it easier to adjust and control the printing process, resulting in the best possible printed structures.  

Know and Control the Temperature

In order to print high quality, void free large scale 3D printed structures, the previous layer must be cool enough to support the new layer without distortioin, but must also be warm enough to fuse completely with the new layer as it is applied. To accomplish this, we must first know and be able to control the temperature of the surface throughout the printing process. There is a narrow range of temperatures for each material where 3D printing is optimal. The goal is to continuously operate within that range.

Real-time Full Color Thermal Image of the Part
 

Thermwood’s new thermographic imaging system shows the operator a full color thermal image of the part as it is being printed. In this image, different colors depict different surface temperatures of the part. With our system, a green color, is assigned to the ideal range of temperatures for the material being printed. The thermal image is displayed on the control screen in a movable, resizable window. The goal is to continuously print on green. 

Easily Adjust Print Speed and Temperature

Once print temperatures are known and the ideal print temperature can be identified, Thermwood’s print head control makes it easy to adjust printing parameters to achieve the ideal print surface temperature. If the part becomes too hot, fan cooling can be increased or print speed can be reduced to allow more cooling time between layers. If the part temperature becomes too cool, print speed can be increased or cooling can be reduced. 

LSAM High-Output Print Heads Are Important

Thermwood’s high output print heads are also important to quality printing of large parts. In the past, trying to print large parts with low output print heads presented a different thermal problem. Slow print speeds prevented the print head from returning to a point before it becomes too cool to achieve a proper layer to layer bond. With Thermwood’s high output print heads (our largest prints up to 500 lbs/hr) this is no longer a problem. Really good quality large thermoplastic composite parts can be made. Our new thermographic imaging system provides temperature guidance and helps the operator to consistently achieve the desired results. 

Three Different Thermographic Camera Mounting Locations

The thermographic camera can be mounted in three different locations. The first is a fixed position on a stand, inside the machine, looking at the part. The second mounting position is on the print gantry. This works well for parts that are too large to view as a single image. The camera can also be mounted to the print head itself, for special applications. Image output from the camera is integrated with Thermwood’s print gantry CNC control and the full color temperature image is displayed on a resizable window right on the control display itself. A touch screen allows the operator to touch any point on the image and read the exact temperature of that point. 

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.  

About the Thermwood LSAM

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.  

Time-lapse Video 3D Printing/Trimming a Mold on the LSAM

Here we present a time-lapse video demonstrating the Thermwood LSAM 3D printing two parts of a mold at once and then trimming. 

About the Thermwood LSAM

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.  

Time-lapse Video

Here we present a time-lapse video demonstrating the Thermwood LSAM 3D printing two parts simultaneously. 

About the Thermwood LSAM

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.