Thermwood has released a brand new machine model that offers a greater range of choices for large-scale additive manufacturing applications. Called the LSAM MT, the new machine offers an all-new configuration and significant advantages in various applications.

Thermwood is a US-based manufacturer of CNC machinery that markets its products and services through offices in 11 countries. Its has also become a technology and market leader in large-scale additive manufacturing (LSAM) systems for thermoplastic composite moulds, tooling, patterns and parts. Its line of LSAM machines can perform both 3D printing and trimming operations on the same machine. Its systems are marketed to major companies in the aerospace, marine, automotive and foundry industries, as well as military, government and defence contractors.

Unlike standard LSAM systems, which feature dual gantries operating over a large fixed table, the LSAM MT (which stands for “Moving Table”) features a single fixed gantry mounted over a moving table. This configuration offers several significant advantages, not the least of which is a dramatically lower price.

Despite the lower price, the LSAM MT is still a massive, robust industrial production machine capable of reliable, day-in and day-out production. Unlike standard LSAM systems, the MT can be configured as a “Print Only” machine. The logic for this is simple.

Near-net-shape printed tools dramatically reduce machining time for many companies currently machining tools from solid blocks of material. This frees up significant machining capacity that is already purchased and installed. For these companies, it makes no sense to purchase additional machining capacity with their additive system, since the change to additive frees up more than enough existing capacity to handle everything they can print. With this in mind, Thermwood decided to offer both “Print and Trim” and a “Print Only” versions of the MT.

The MT is available in two table sizes – 10 ft (304cm) wide x 5ft deep, and ten feet by ten feet. The larger machine actually has a table measuring ten feet by 12 feet, with a ten-by-ten-foot working area. The extra two feet is used to mount an optional Vertical Layer Print table. The larger MT machine can be equipped with a new version of Thermwood’s patented Vertical Layer Printing technology. This means that it can make parts up to ten feet by ten feet and five feet high using traditional Horizontal Layer Printing. or five feet by ten feet and ten feet high using Vertical Layer Printing.

Since the print technology and print heads used on the MT are the same as those used on Thermwood’s larger machines, it offers the same throughput, print quality and layer-to-layer fusion that has made Thermwood a leader in LSAM. As with the larger systems, the MT can process high-temperature polymers, which are ideal for autoclave-capable tooling or compression moulds for thermoset materials.

With the addition of the MT, selecting the best size and configuration for an LSAM may not be quite as straightforward as it first appears. It depends on two major factors plus some additional considerations. The major factors are the material being printed and the size of the parts needed. Of these two, the material being printed is the most significant.

For the purposes of machine selection, reinforced thermoplastic composite materials for room-temperature or low-temperature applications such as foundry patterns, boat plugs, boat and yacht moulds, building structures and other similar applications can generally be bonded securely with a variety of industrial adhesives. For these type of parts, even for really large parts, the smaller less expensive machine may be a better choice. The part can be separated into sections, which can be printed individually and bonded into the final, potentially extremely large structure.

Although it seems counter-intuitive, this approach can be faster than printing the large structure as a single piece on a larger, more expensive machine. To better understand, it is necessary to consider the basics of the print process. Additive manufactured parts are printed in layers. The speed at which a layer can be printed depends primarily on how long it takes for the polymer being printed to cool enough to support the next layer. This layer cooling time depends on the polymer and is not affected by the size of the part. Each layer of a particular polymer takes the same amount of time, regardless of how big it is.

LSAM print heads can print faster – sometimes significantly faster – than is needed for most parts. Often it can print two, three or more parts in the cooling time required for each layer. The large machine is only printing a single part, one layer at a time, making it two or three times slower. To print the part in one piece, the large machine must operate continuously, around the clock, sometimes for days. This is not a problem for factories that operate on all three shifts, but it can present staffing problems for single-shift operations. With the MT, several different segments of the same part can often be printed in a single shift. Depending on the item being printed, it is possible to print as much in a single shift as the large machine, printing a single part, can do in 24 hours.

For large parts made from bondable materials, often the smaller, less expensive machine is a better choice.

Materials intended for high-temperature applications – such as PSU, PESU, PEI, or Ultem – generally are resistant enough to solvents that they can’t be effectively bonded. Even if they could, few if any adhesives exist that can withstand the operating temperature or the thermal cycling these materials experience. For these applications, the machine needs to be large enough to print the part in one piece, even though it could be slower. This is where larger machine configurations are needed. The larger machines also offer the ability to print and trim at the same time, which may be beneficial in some circumstances.

Since the print heads are the same on all Thermwood LSAMs, the smaller MT can be used for these high-temperature parts, provided they fit in the available envelope. Just like the standard LSAMs, the MT comes complete, fully engineered, with everything needed for production operation.