Choose the Right 3D Printer and Printing Technology for Manufacturing Process

This article serves as a source of information for engineers, manufacturers, and product developers looking to add a 3D printer to their manufacturing process. The guide will concentrate on printers and printing technologies best suited for manufacturing applications.

There are several options for printers and materials that offer the strength and chemical resistance necessary for manufacturing environments. The primary uses for 3D printed parts for manufacturing are prototyping, tooling and fixtures, and low-volume end-use parts.

Table of Contents

What is Additive manufacturing?
Common misconceptions about 3D printers
Let’s talk ROI
Machining in-house
Sending out to a third-party supplier
3D printing in-house
Working out ROI
Business Impact
Types of 3D Printing technologies
Thermoplastics
Photopolymer
Composite
Metals
How to choose a 3D printer for your company

What is Additive manufacturing?

Additive manufacturing is a process in which a machine makes a three-dimensional object from a CAD (computer-aided design) file. In comparison, subtractive manufacturing methods involve removing material from a blank piece of stock. 3D printing is a subset of additive manufacturing and is just one of how people and businesses fabricate 3D objects. Traditional subtractive manufacturing is notoriously slow, expensive, and has design limitations, whereas additive manufacturing is paving the way for quick, low-cost processes.

Additive manufacturing, sometimes used interchangeably with 3D printing, was first used as a pure prototyping tool. The first 3D printer was invented by the American inventor Charles ‘Chuck’ Hull, who patented a process back in 1984. A few years later, in 1986, Hull coined the term stereolithography and the concept of rapid prototyping.

Today, some 35 years later, additive manufacturing is used not only for prototyping but also for tools and end-use parts. Its use spans industries such as tooling, automotive, dental, life science, architecture, and aerospace.

3D printing is helping companies reduce weight, create complex geometries, and optimize functionality in many different types of applications. The selection of materials grows each day, and include polymers, metals, ceramics, carbon fiber, and precious metals.

Common misconceptions about 3D printers

Although 3D printing has been around since the 1980s, it has often been misrepresented — both positively and negatively. Unfortunately, 3D printed parts are often synonymous with figurines, hobbyist parts, and cosmetic prototypes. However, thanks to innovations in technology and materials, there’s so much more that companies can achieve with a printer built for manufacturing floors.

Some people shy away from new technology when misinformed, while others criticize it. The following common misconceptions about 3D printers and their materials should uncover the truth about how this technology is aiding the industry, not hindering it.

Myth: Plastic 3D printing materials are too weak to be used in a manufacturing environment

Before 3D printers built for manufacturing were introduced, many low-cost machines were printing plastics not suitable for a manufacturing environment. The parts they made were not only weaker but also not durable enough nor chemically resistant. In the last five years, 3D printer manufacturers have created machines capable of printing more robust materials. The addition of composites such as continuous carbon fiber has introduced the ability for customers to print parts that are both chemically resistant and durable, and when reinforced with continuous carbon fiber, parts are as strong as 6061 aluminum, a commonly used material in manufacturing applications fit for 3D printing.

Myth: 3D printers capable of printing parts strong enough for manufacturing are expensive

Some manufacturing-grade printers are expensive, however, you can find a 3D printer for manufacturing purposes from 3,500 euros. The ones costing over 100,000 euros are usually large format plastic printers or metal printers, which frequently require special facility requirements and safety equipment.

Myth: 3D printers are hard to use

3D printers for manufacturing purposes often have unintuitive software that requires expert knowledge, while most hobby-level 3D printers are built without software. As a result, these machines require considerable expertise — such as how to design a part for the process, how to orient and position a part, which material to use — to yield a viable part. 3D printer companies now produce integrated, purpose-built hardware, software, and materials, resulting in predictable machine performance. This means engineers and machinists can focus more on creating quality parts and less time focusing on figuring out how to operate their printer.

Myth: 3D printers will replace high-volume production

The time and cost required to 3D print parts at high volume are often far greater than that of traditional manufacturing. Producing at scale has been optimized for decades, so 3D printing is currently not fast or cost-effective enough to replace processes like injection molding or casting. However, many companies find that adding several printers to their manufacturing processes can significantly reduce time spent fabricating complex parts in-house.

3D printers can create parts faster and at a low cost for custom low-volume parts. Businesses can focus on revenue-making end-use parts, instead of focusing time, effort, and money on low-volume parts that may not generate any revenue for the business. With a 3D printer, you can rapidly iterate designs without wasting resources waiting for parts. This makes 3D printers perfect for low-volume, custom-made prototypes, tooling, and fixtures.

Let’s talk ROI

A 3D printer is a large investment that lacks the institutional maturity that suggests it will fit in as well as traditional manufacturing capital expenditures. If you haven’t used a 3D printer for manufacturing purposes previously, you may have not calculated the potential ROI. However, the addition of a 3D printer is capable of drastically reducing manufacturing costs for parts like prototypes and tools. Below we will compare 3D printing to machining in-house and third-party suppliers, as they are the most common processes.

Machining in-house

Machining a part in-house requires money spent on equipment, material, and a machinist’s time. If you value your machinist’s time at 65 euros/hour, and it takes them five hours to set up, program tool paths (CAM), and machine the part, that’s 320 euros of labor towards a part. Material costs also add up, and iterations and revisions contribute extra costs.

Sending out to a third-party supplier

Sending a part out to a third party is an easy way to fabricate a part without setting aside internal manufacturing resources. It is, however, quite costly when making low-volume parts. If you’re sending out a part to be made, you need to wait for it to be made and shipped. If you find you need to make some iterations, you will have to pay for each iteration plus shipping, and can’t make further modifications until you receive your part.

3D printing in-house

3D printing a part in-house includes a one-time machine cost and ongoing material costs. Your machinists can manage each print via cloud-connected software and focus on creating important parts instead of overseeing the machine while it works. Some 3D printers come with software that will tell you how much the part you’re designing costs to print, meaning you can monitor the second part of your cost (the material cost) through software.

Working out ROI

Use the table below to work out the number of parts it will take to pay off a 3D printer. In this example, we’re using Markforged’s X7 Industrial Series printer as the benchmark printer, and three different parts (gripper jaws, CMM fixture, welding fixture) for benchmark parts. Take your current manufacturing method costs and subtract the cost of the printer to get cost savings per part. Take the price of the printer and divide it by the cost of the savings to work out how many parts you need to print to pay off the machine.

Business Impact

Business benefits spread far further than reduced costs and time-related to part production. Here are a few areas where manufacturers have benefited by utilizing 3D printers:

• Design flexibility: Make parts that were otherwise unable to be fabricated traditionally
• Faster time to market: Ship products faster by running your 3D printer 24/7
• Greater agility: Achieve more flexibility for small modifications, reducing turnaround time
• Less machine downtime: Continuously innovate with minimal downtime

Types of 3D Printing technologies

Thermoplastics

Thermoplastics are one of the most common material groups in additive manufacturing.

Thermoplastic 3D printing processes involve heating a plastic material to just below its melting temperature where it is semi-formable to create a shape.

Thermoplastics are tough but weak, deforming rather than fracturing under stress. They have relatively low melting points, and low chemical and abrasion resistance.

FFF (Fused Filament Fabrication)

Best applications: Low-fidelity prototypes and models.

How it works: FFF is the most widespread 3D printing technology. In this process, the thermoplastic material is heated and extruded through a nozzle. As the nozzle moves, it deposits a cross-section of the model being printed. This is repeated layer by layer until the model is completed. FFF parts are generally not fully dense.

Pros:

• Simple
• Affordable
• Lightweight parts

Cons:

• Weak parts
• Parts prone to wear

SLS (Selective Laser Sintering)

Best applications: High-precision end-use parts.

How it works: SLS utilizes a laser to sinter powdered plastics into shape. The parts are printed in a chamber of plastic powder. For each new layer, a roller sweeps new powder over the chamber, and a laser selectively sinters a cross-section of the part. By using SLS, you can create incredibly high-quality parts with high-strength plastics.

Pros:

• High detail
• Wide range of materials

Cons:

• Expensive
• Respiratory protection required

Photopolymer

Photopolymer materials are liquid polymers that change structure when exposed to a light source.

When catalyzed with UV radiation, these liquid resins solidify. Unlike thermoplastics, photopolymers cannot be melted.

Resins are often brittle and not as long-lasting as thermoplastics, as they degrade over time from continued UV exposure.

SLA (Stereolithography)

Best applications: High-precision detailed parts such as form prototypes or models.

How it works: The SLA process selectively cures photopolymers with a UV laser. The laser cures the resin to form a hardened layer, then repeats the process layer by layer until complete. As the chemical bonding process is induced by photopolymerization, printed parts are dense and isotropic. SLA 3D printers often have a relatively small build volume, but can achieve exceptional detail and surface finish through the precision of the laser beam.

Pros:

• Highly detailed
• Smooth surface finish
• Isotropic

Cons:

• Brittle parts
• Small build volume
• Chemical protection required

Composite

Composite materials are highly valuable because of their material properties. Well-known and heavily utilized composites like carbon fiber reinforced resins traditionally deliver high strength-to-weight ratios for industries such as automotive and aerospace.

With the recent innovation of 3D printable composite materials, parts can be made strong enough for use in engineering applications in which the material properties of more common printing methods would not be sufficient.

In 3D printing, a thermoplastic reinforced with continuous carbon fiber can effectively replace traditionally machined aluminum components, because it combines the strength and stiffness of metal with the ease of additive manufacturing.

FFF (Fused Filament Fabrication)

Best applications: Functional prototypes, customized end-use parts.

How it works: Composites FFF uses materials composed of traditional thermoplastics like nylon and PLA mixed with chopped fibers (usually carbon fiber). While the FFF process remains unchanged, the chopped fibers increase the strength, stiffness, and surface finish of the model.

Pros:

• Heat deflection
• Precision
• Strength

Cons:

• Limited range of materials
• Medium-strength parts

CFF (Continuous Filament Fabrication)

Best applications: Functional prototypes, strong end-use parts, tooling, and fixtures.

How it works: CFF is a cost-effective solution for replacing metal parts with 3D printed composite parts. Printers use a second nozzle to lay strands of composite fibers within FFF-extruded thermoplastics. The reinforcing fibers form the backbone of the printed part, resulting in strong, stiff parts.

Pros:

• Metal-strength parts
• Customizable fiber pathing

Cons:

• Inter-layer adhesion
• Lower surface hardness and corrosion resistance vs. metal

Metals

3D printing metal has been limited by cost, complexity, and some material constraints until recently. Metals cannot be extruded quite as easily as thermoplastics, and they require high heat and power to achieve a formable state.

To implement metal additive manufacturing, most solutions start with the metal in powder form and use various heating techniques to fuse the powders.

Many metal printing methods include post-processing steps to fully strengthen or finish the printed parts from continued UV exposure.

SLM/DMLS (Selective Laser Melting / Direct Metal Laser Sintering)

Best applications: High-precision parts requiring great dimensional accuracy.

How it works: SLM is achieved by precisely melting fine metal powders to build up a metal part. Layers of the metal powder are distributed and then selectively melted with a high-power laser to fuse the powders. The process can be used for functional metal parts that would be too expensive or complex to machine (such as medical implants and weight-optimized parts). There are also multiple post-processing operations to remove supports and clean the part, so specific facility requirements are necessary.

Pros:

• Strong parts
• Intricate detail
• Excellent surface finish
• Wide range of materials

Cons:

• Expensive
• Part failure
• Extensive post-processing steps

Binder Jetting

Best applications: Complex large parts such as cooling systems, housings, and aerospace parts.

How it works: Binder Jetting is a process where a layer of powder is deposited on a build platform. A liquid bonding agent is applied, which bonds the particles together. The print head drops alternating layers of the material and the binding material layer by layer. Binder Jetting does not require any support structures, meaning the build volume can be filled with several parts. Binder Jetting is a cheap and fast process and can work with almost any material that comes in a powder. After printing, the part needs to be washed and sintered in an oven to make it a fully dense metal part.

Pros:

• Fast
• Cost-effective
• Many materials available

Cons:

• Fragile parts
• Extensive post-processing time

ADAM (Atomic Diffusion Additive Manufacturing)

Best applications: Metal tooling and complex parts.

How it works: ADAM is a unique and cost-effective metal 3D printing process that combines concepts from FFF 3D printing and Metal Injection Molding (MIM). Metal powder (common to SLM methods) is encased in a plastic binder, which gets deposited layer by layer on a print platform by an extruder. After a part is finished printing, it needs to be washed and sintered in an oven, melting away the binder and allowing the metal powders to fuse into an isotropic metal part. ADAM is also useful for building custom internal geometry.

Pros:

• Custom infills
• Cost-effective
• Wide range of materials

Cons:

• Not fully dense
• Can’t produce small, precise features

How to choose a 3D printer for your company

When choosing a 3D printer, ask yourself these questions:

• What are our biggest manufacturing challenges?
  • Prototyping (number/time of iterations, lead time/cost)
  • Tooling (time/cost to tool up, custom tooling)
  • End-use parts (cost, quality, lead time)
• What are my current costs for outsourcing or machining parts inhouse?
• How important is it to have strong parts?
• Do my parts need to be resistant to heat or chemicals?
• Do I have specific material restrictions? (thermoplastic, composites, photopolymers, metal)
• Am I currently missing deadlines because of the time spent machining or outsourcing parts?
• Is the company losing revenue due to reduced production?
• Are our engineers relying too heavily on expensive equipment for non-revenue parts?

If you get the chance to speak to a few 3D printer companies, ask them these questions:

1. What’s makes this company’s technology unique?
2. What are the facility’s requirements for machine operation (health, safety, power, and ventilation)?
3. Is it possible to get samples to test the quality?
4. What is the process from design to part in hand?
5. What are the specific steps involved to get to a functional part ready for my factory floor?
6. How does your system assure great print quality?
7. What materials can I work with on each machine and how will these support my application?
8. What does the setup process look like, including training, and how quickly am I printing?
9. Who typically operates printers in-house and what kind of training/ expertise is required?
10. Can you test software in advance?
11. Does the printer come with its software?
12. What’s the learning curve for the software?

Once you have the necessary information, you’ll be able to make an informed decision about which printer works best for you.

Source: PLM Group