Production Guide: Choosing the Right Process for Your Custom Parts

Last Updated: July 25th, 2018


Introduction

Xometry offers a number of different means to make parts for every application and stage of the prototyping and production process.

Most of our parts are produced using the following methods:

CNC Machining, Sheet Metal, 3D Printing, Casting, and Molding.

Many innovative manufacturing processes can be harnessed to prototype and produce end-use parts faster and more cost-effectively than ever before. We are here to help guide you through the options and will always be available to make recommendations once you’ve uploaded your CAD file.


Computer Numerical Controlled (CNC) Machining

CNC Machining offers unparalleled precision for producing metal and plastic parts.

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Highlights

Extreme Precision and High Quality
CNC Machining is one of the fastest, most accurate methods available to build market-quality parts for almost any application. CNC removes material using high speed, precision machines that are programmed to use a wide variety of cutting tools to create the final design.

Fast Delivery
Xometry can machine parts in most common metals and plastics in as little as 6 business days. Our standard lead time for most orders is 10 business days.

Economical with Minimal Setup
We offer 5-axis CNC Machining to produce appropriate parts quickly and with minimal setups.

Trade-Offs

  • Given the cost of material and setup, CNC Machining can be more expensive for smaller quantities of parts.
  • Certain features, such as those that cannot be reached by the milling tool, cannot be produced.
  • Sharp interior corners must have a radius of at least 0.0156”, and square interior corners will have a corner radius of 1/8 times the depth of the pocket applied.

Featured Resources

Ready to quote in CNC Machining? Upload your 3D CAD file to get started.


Sheet Metal Fabrication

Sheet Metal produces durable, end-use metal parts that are fabricated to your specifications.

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Highlights

Production Quality
We currently offer sheet metal fabrication services including bending, punching, and cutting many different metals to form your part for either low to high volume production runs. Parts are well known for their durability and precision, which makes them perfect for end-use.

Durable, Uniform Thickness
Sheet metal fabrication produces thin-walled, metal parts that can’t be produced with CNC Machining. Chassis, enclosures, and brackets are perfect for Sheet Metal Fabrication because they maintain a uniform thickness and need to be rigid and durable.

Quantity Discounts
As quantity increases, price per part drastically decreases due to the fact that parts are able to be patterned on the same stock of material.

Trade-Offs

  • Sheet metal may be expensive for lower quantities of parts due to tooling, setup and material costs.
  • Sheet metal fabrication cannot be used for parts with non-uniform or large wall thicknesses.
  • Sharp interior corners are incompatible with this method, as the sheets are bent with machinery that has rounded corners.

Featured Resources

Sheet Metal Mini-Guide

Sheet Metal Mini-Guide

Sheet metal fabrication is a process by which metal parts are cut and bent from a roll of stock material that is typically less than 0.25” thick.

Ready to quote in Sheet Metal? Upload your 3D CAD file to get started.


Urethane Casting

Urethane casting provides end-use, rigid or flexible plastic parts with production-level quality.

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Highlights

End-Use Durability
Parts made with urethane casting are great for applications such as automotive and aircraft parts due to their ability to be produced quickly and at a low price, while being durable enough for end-use.

Mechanical Property Range
Depending on the mixture, urethane casted parts can be either rigid, flexible, or rubber-like and are even sufficient for end-use applications due to this method’s high impact strength, abrasion resistance, and resistance to heat.

Faster than Injection Molding
Urethane casted parts are known for “bridge tooling” or “soft tooling” when compared to Injection Molded parts because of the faster rate of production and lower fixed cost.

Trade-Offs

  • Quantities are limited by both time and durability of the silicone molds, due to the fact that parts need to solidify and can only manufactured one at a time.
  • Shrinkage may be unpredictable depending on the geometry of the part.

Featured Resources

Three Benefits of Urethane Casting

Three Benefits of Urethane Casting

Whether you’re a Fortune 500 company or a start-up looking to beat your competitor to market, striking the right balance between high-quality, end-use parts and production lead-time can be a headache.

Ready to quote in Urethane Casting? Upload your 3D CAD file to get started.


Injection Molding

Injection Molding provides top performance and cost efficiency for high-volume production parts.

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Highlights

Variety of Material Properties
The Injection Molding process offers a vast array of plastic resins to work with. These materials have been developed to meet specific requirements for strength, high temperature and chemical resistance, abrasion resistance, and low friction.

Thin Walls? No Problem
Unlike many other manufacturing methods, thin walls actually benefit Injection Molded parts by reducing cycle time and, by extension, part cost.

Precise Surface Finish
Molded parts will carry the exact surface finish of their molds, allowing for greater control over the finished product.

Economy of Scale
Since large numbers of uniform parts can be produced from a single mold, Injection Molding is an excellent choice for production runs—the more you buy, the less you spend per unit.

Trade-Offs

  • Shrinkage varies based on material and must be compensated for in the mold.
  • Cost-prohibitive in small quantities, Injection Molding is best for low-volume production runs.
  • The molded part will pick up even the smallest imperfection in the mold surfaces, so additional finishing of the mold may be required.

Featured Resources

Ready to quote in Injection Molding? Upload your 3D CAD file to get started.


Stereolithography (SLA)

SLA is a powerful 3D printing technology that produces extremely accurate and high resolution parts that are capable of being used directly in end-use, low-volume production, or for rapid prototyping.

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Highlights

Smooth Moves
SLA parts are printed with almost glassy finish—smoother than other 3D Printing processes—due to their UV curing process. (Note: matte finish is also available.)

Physical Snapshots
Combining high resolution prints with speed and versatility, parts printed in SLA allow product developers to see their designs come to life quickly and cost-effectively throughout the iterative process.

Detail-Oriented
SLA's precision and fidelity allows for highly detailed features, such as embossing, that are not always possible with other 3D Printing processes.

Trade-Offs

  • Long and broad are subject to uneven curing, which can lead to warping. They are also more susceptible to distortion caused by heat and moisture which can happen during post processing or shipping.
  • As with most 3D Printing processes, there is risk of especially small features not resolving. Be sure to meet minimum suggested dimensions to avoid resolution errors.

Featured Resources

3D Printing is Not a Cheat Code

3D Printing is Not a Cheat Code

Get expert insight on understanding 3D Printing from our own Director of Applications Engineering, Greg Paulsen. Learn how to make the most of this additive manufacturing capability with his expert tips.

Ready to quote in SLA? Upload your 3D CAD file to get started.


Direct Metal Laser Sintering (DMLS)

DMLS is a 3D printing technology that uses metal powders and precision lasers to quickly and accurately create complex parts from a 3D CAD file.

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Highlights

Speed Meets Durability
DMLS is a 3D printing technology that uses metal powder and precision lasers to quickly and accurately create fully-dense parts from a 3D CAD file. DMLS is great for applications that require robust and complex parts in a short lead time. Parts typically ship in 4-8 business days!

High-Performance Materials
Xometry offers DMLS in Aluminum, Stainless Steel (316L and 17-4), Titanium, and Copper.

Production Quality
The durability and strength of DMLS parts up to 980 MPa in stainless steel makes them perfect for end-use applications. These parts are also useful for injection molds, and fully functional late-stage prototypes.

Trade-Offs

  • DMLS cannot produce the smooth surface finish of a machined part. Pieces can be manually polished, but process is time-consuming and makes tolerances difficult to maintain.
  • Parts require support structure for overhangs greater than 45 degrees from vertical. Fillets are great to allow surfaces to be self-supporting and grant more freedom of design.

Featured Resources

Video: How Will It Grow?

Video: How Will It Grow?

What causes metal 3D Printed parts to warp, distort, or have inconsistent features?! Watch our new video to see what factors create a successful DMLS part, and how to implement them for your next project.

Ready to quote in DMLS? Upload your 3D CAD file to get started.


Fused Deposition Modeling (FDM)

FDM is a 3D printing technology widely known for its speed, accuracy, and competitive cost.

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Highlights

All-Around MVP
FDM is widely known for its speed, accuracy, and competitive cost. These factors make it a good choice for concept models, prototypes, and end-use parts.

Trusted Materials with Excellent Mechanical Properties
FDM 3D printing builds parts layer by layer using an extruded thermoplastic filament. Its robust material options make it a great fit for applications that require proven, high-performance plastics such as ABS, Polycarbonate, PPSF, and Ultem.

Color Customization
We offer an enormous amount of customization for FDM parts with 16 colors to choose from, depending on the material.

Trade-Off

Bead thickness causes FDM to sweat the small details, and have noticeable layer stepping. As a result, small holes, text, very narrow pegs and lips may not resolve (for these types of features we recommend SLS or PolyJet).

Featured Resources

Video: Will It Break?

Video: Will It Break?

We put these 3D Printing materials to the test. Find out the results of our impact resistance challenge!

Ready to quote in FDM? Upload your 3D CAD file to get started.


PolyJet 3D

PolyJet offers one of the most advanced industrial 3D printing solutions available, producing parts with incredible precision and speed. It also supports a wide variety of build materials.

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Highlights

Incredible Speed and Precision
PolyJet 3D printing builds parts layer by layer using UV light to cure a jetted resin. It offers one of the most advanced industrial 3D Printing solutions available and, due to its simple pre- and post-processing procedures, allows for quick lead times.

Smooth Finish
This process is known for resolving very fine details and producing a smooth surface finish. Polyjet builds parts in fine layers using a UV-cured photopolymer deposited through jetting print heads. It is widely used for models, prototypes, and (low-heat) molds.

A Wide Variety of Properties
Parts in PolyJet can be printed in materials with many different properties from rigid to rubber-like, and even translucent. PolyJet machines can also run multiple materials simultaneously or blend materials together! This drastically increases the variety and characteristics a part can come in.

Trade-Offs

  • PolyJet materials tend to be more fragile than FDM or SLS parts. We recommend using it for fit-checks, “feel” checks, trade-show models, and other uses that do not involve harsh environments or impact.
  • Small features on PolyJet parts pose a high risk of breaking off during post-processing. We recommend adding drafts, fillets, and ribs to strengthen the part. Thin and narrow sections of a part are most vulnerable to break.
  • Support material is needed for certain features, which could reduce the freedom of design because removal of support may risk breaking fragile features.

Featured Resources

Video: Will It Break?

Video: Will It Break?

We put these 3D Printing materials to the test. Find out the results of our impact resistance challenge!

Ready to quote in PolyJet? Upload your 3D CAD file to get started.


Selective Laser Sintering (SLS)

SLS is a powerful 3D printing technology that produces highly accurate and durable parts that are capable of being used directly in end-use, low-volume production.

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Highlights

The Power of Nylon
SLS prints parts in Nylon 12, making it a robust and “forgiving” process due to nylon's inherent toughness and flexibility (including a high degree of chemical resistance). Nylon can also be sterilized via steam autoclave, Et0, plasma, chemical, and gamma methods. We consider SLS to be one of the best general-use processes for both prototyping concept models and for low-volume manufacturing of end-use parts.

Complexity Without Support
SLS parts are built in a self-supporting powder bed which allows fine details, overhangs, and lattice structures to grow easily in all directions. This makes it a great method for complex parts.

Economical and Fast
Because parts are “free floating” and can be nested together in a build, SLS is a very cost-effective process.

Watertightness and sealing
Parts that are over 0.040” tend to be water tight and fully dense. Sealing surfaces may require manual smoothing due to the matte finish of sintered plastic.

Trade-Offs

  • Smoothing surface requires sanding or machining.
  • Materials are limited to unfilled and glass-filled nylon.
  • Larger parts tend to suffer from thermal stress which causes warping or unpredictable shrink.

Featured Resources

Ready to quote in SLS? Upload your 3D CAD file to get started.