How is an industrial 3D printer constructed and what functions do its parts

3D printing has revolutionized industrial manufacturing and prototype construction. This technology produces objects layer by layer from a digital model. Consisting of the main components: In addition to a frame, print head, printing bed, control unit, shafts, toothed belts and motors, a typical 3D printer design generally also requires a number of accessories. But how exactly does an industrial 3D printer work? This article highlights the structure and function of the most important components and briefly names some areas of application.

A 3D printer creates three-dimensional objects by applying material layer by layer based on a digital model. This is also referred to as the additive manufacturing process, since material is incrementally added to the unfinished workpiece.

The process begins with a digital design file, often delivered in STL (STL = Stereo Lithography) format. This is loaded into a special software with which the 3D model is converted into a control file that is understandable for the 3D printer. This file is converted into the so-called G-code (G-code is a machine language for programming CNC machines). The data model is broken down by a slicer software into G-code layers or thin horizontal layers. This process is called slicing.

The printer reads this file and successively prints the layers by applying and solidifying the material - often plastic, resin, or metal powder - layer by layer until the entire object is created.

The exact process varies depending on the printing technology, for example, whether the material is melted by heating (FDM) or hardened by exposure to light (SLA). The following printing technologies are currently available:

• Stereolithography (SLA): A thin synthetic resin layer is poured into a tray. A UV laser then exposes the areas to be cured. A 3D printer enclosure is used for this technology.
• Masked Stereolithographie (MSLA): The MSLA printing process selectively illuminates the synthetic resin from below with an LCD display. The LCD display forms a mask for each printing layer and thus blocks the UV light at the specified locations. Instead of a laser beam that scans the layers, MSLA printers use a high-performance ultraviolet light source.
• Selective laser sintering (SLS): Various materials in powder form are distributed on the printing plate and melted by means of lasers. Finally, the finished product must be freed from the surrounding powder.
• Fused Deposition Modeling (FDM): The layer melting process brings the material onto the printing plate with a heated nozzle, where it is then solidified.
• Luminated Object Manufacturing: The material is built up layer by layer glued on top of each other and is subsequently modeled with a cutting tool (laser or knife).
• Computed axial lithography (CAL): The CAL printing process projects light into a liquid, light-sensitive resin, which then rapidly solidifies. This method allows objects to be manufactured in the shortest possible time.

Structure of a 3D printer

Industrial 3D printers have certain basic components that are used based on the selected printing technology.

3D printer frames

The frame is the basic mounting structure for all electronic and structural 3D printer components and also forms the basis for high-quality printing. It gives the printer stability and structure. The stiffer and rigid the frame, the better the printing results. In industrial printers, the frames are often made of robust metal alloys to minimize vibration and to ensure high printing accuracy. At MISUMI you will find a wide range of frame components of high quality, such as aluminum design profiles, accessories for linear guides or angle plates.

Axes in 3D printers

Within a fixed three-dimensional space, the industrial 3D printer must be able to reach every point to ensure the printing of all conceivable shapes. There are the following axes for this:

• X-axis: Describes the path horizontally from left to right
• Y-axis: Describes the path horizontally from front to back
• Z-axis: Describes the path vertically from top to bottom

The print head moves along the X-axis and Y-axis, for example by means of toothed belts and stepper motors.

The vertical movement is realized by a stepper motor. Rotary movement is transferred by a toothed belt to a lead screw or a screw drive. The stroke of the Z-axis determines the thickness of the applied material layer.

The precision of the individual transfer components is decisive for the quality and dimensional accuracy of the object to be printed.

Print head (extruder) of 3D printers (FDM)

The extruder conveys the filament (printed material) from the raw material source, e.g. a filament roll, into a heating block with heater and temperature monitoring. This area is also called the hot end. The liquefied filament is conveyed through this channel to the nozzle (nozzle) and is applied to the printing plate.

There are different types of filament transport through the extruder. Here are some of the most common types:

• Direct Drive (Direct Drive Extruder): For this method, a motor directly pulls the filament into the extruder, where it is then transported into the heating block. The motor is located in the immediate vicinity of the nozzle, which leads to a more precise material application. This method is often used in desktop 3D printers.
• Bowden extruder: In contrast to the direct drive, a Bowden extruder does not have the motor directly on the extruder. The filament is conveyed to the extruder through a flexible tube (Bowden tube). This reduces the weight of the extruder, which can have a positive effect on the print quality. However, the accuracy of the filament conveyance may be slightly impaired in this method.

Both variants can be equipped with several print heads, so that different materials and colors can be processed. If the 3D printer uses a powder instead of a filament, extruders are usually not used; rolls are used instead to apply the material to the print bed.

Print bed (build plate) in 3D printers

The object is built up layer by layer on the print bed. It can be heated to ensure better adhesion of the material, to avoid material warpage, and to achieve an improved surface finish. The material of the print bed also influences adhesion. Glass, ceramic or cast aluminum plates are particularly suitable here. It is also possible to facilitate the removal of the end product by means of removable plates.

Control unit in 3D printers

The control unit controls the entire printing process. It can also be used to calibrate the 3D printer. The calibration process is of crucial importance to prevent printing errors. An uneven print bed or incorrectly adjusted nozzles have a significant influence on the quality of the end product.

The control unit must interpret the digital 3D model information from an STL file or other file format. For this purpose, the control unit uses slicing software to divide the 3D model into a sequence of horizontal layers (slices). Among other things, information about the layer height, the diameter of the nozzle opening (nozzle size), the printing parameters, the extrusion of the printing material, the temperatures and the tool paths of the print head, and the resulting G-code is generated from this.

The control unit controls the drives of the 3D printer to precisely move the print head and the print bed. It converts the movements defined in the G-code, taking velocity, acceleration, and deceleration into account.

The control unit controls the extruder that heats the printing material, such as filament, and applies it evenly to the build plate to ensure that the material is distributed evenly. The temperature in the 3D printer, the extruder and the heating elements are monitored and controlled.

Of course, the control unit monitors the printing process for errors and irregularities and reacts accordingly to any problems, such as material jam or overheating.

A graphical user interface (GUI) serves as an interface for the user to start the printing process, to adjust settings, to control the printer, and to receive status messages and interact accordingly. This can be done with a display or a touchscreen.

The control unit can communicate with external devices over interfaces to receive print jobs and to exchange data.

Shafts in 3D printers

Shafts are used as a transmission element and as guide components to enable the movement of components, material, print heads, and other important components.

When shafts are used as the transmission element, a movement is transmitted from the drive source to the output side. This is done in combination with, for example, motor, v-belt pulleys and toothed belt pulleys, belts, chains, couplings, gears or other elements.

Some 3D printers use ball screw drives instead of conventional screw guides. Ball screw drives are more precise and have less friction than conventional screw guides. This leads to even better print accuracy.

As guide elements, shafts enable the precise movement of the print head or the print bed in different directions. They are usually cylindrical and made of robust materials to ensure accuracy and durability. The shaft is usually smooth and has high surface accuracy to allow low-friction motion. To guide the shaft and allow for motion, special linear bearings or linear guides are mounted along the shaft.

Toothed belts in 3D printers

Toothed belts convert the rotary motion of the motors into linear motion of the moving parts of the printer. For example, the print heads are moved along the X-axis and Y-axis. They play a decisive role in the speed and precision of the printing process. A firm fit and flawless quality is crucial. Otherwise, there may be reverberations that distort the end product. Toothed belts are usually made of elastomeric materials with inserted tooth reinforcements in order to enable precise transmission of force.

MISUMI offers different toothed belts, shafts and other accessories for both linear and rotary movements. You are guaranteed to find a component for your specific application.

Motors in 3D printers

Motors play a key role for moving and positioning the print head or the print bed. There are different types of motors used in 3D printers, each of which fulfills specific tasks. Here are some of the most common motors found in 3D printers:

• Stepper motors: These move the print head and the print bed in precise steps along the various axes.
• Servo motors: They offer high speed and accuracy and are used where precise control is required.
• DC motors: Are used, for example, for operating rollers.
• Extruder motors: Are responsible for the extrusion of the printing material.

Industrial 3D printing uses the following material categories: filament, resins and powder. Filament is a long, narrow strand consisting of various plastics, e.g. PLA or nylon. It is rolled up on coils and is mainly used in the FDM printing process.

In order to minimize the visibility of the individual layers when using filament materials, the parameters can be adjusted in the settings of the slicing software. Subsequent surface finishing, such as by grinding, filling, coating, painting, or by various welding methods, can be necessary.

Powder-based printing methods enable the production of complex geometries and functional parts. Metal, plastic or ceramic powders, for example, can be used as the material.

The printing process with resins uses liquid resins, which are hardened under the influence of UV light or laser beams to build up the print layers.

Various resin materials are available that offer a variety of properties, such as hardness, flexibility, temperature resistance and transparency. This material is very well suited if the print object requires precision and accurate details.

Possible uses of 3D printers

Within a very short time, 3D printing has conquered many areas of our life, including mechanical engineering, custom machine construction and prototype construction. The rapid turnaround by which components can be manufactured is particularly interesting for many industrial businesses. Not only can storage space be reduced over the long-term, but changing circumstances and special applications can also be proactively addressed.

Use of 3D printers can in particular accelerate product development with rapid prototyping.

The ability to create complex geometries allows designs and shapes to be quickly adapted to current R&D concepts.

This allows design errors and problems to be identified and fixed early before mass production begins.

In some cases, the prototype itself can serve as a template for mass production, especially for small batch production or individualized products.