Evaluation Checklist: Seventeen Things to Consider When Reviewing 3D Printers
Todd Grimm posted on January 27, 2012 |
Looking to add a 3D printer to your stable of engineering and manufacturing tools? For a thorough co...

By Todd Grimm, Editor

In Short
  • Seventeen measures for thorough evaluations.
  • Get all the data and then compare in a weighted matrix.

Looking to add a 3D printer to your stable of engineering and manufacturing tools? For a thorough comparison, go beyond general perceptions of speed, cost and quality.

Following are 17 items to include in your evaluation checklist. These will show you real-world results that will lead you to the right choice.

Time

Don’t settle for build speed alone. It is only one element of the time to produce a ready-for-use part. Instead, investigate the total process time. And do so with your parts — good representative samples of the objects you will make — and the material you plan to use.

1. Preparation

Process time chart

Preparation and post-processing (red), when combined with build time (blue), dictate total time for delivery.

Consider both the time to prepare files for building and the time to set up the system.

For file preparation, consider how long it takes to manipulate all the build settings; how long it takes to slice and support a file; and how long it takes to prepare the buildable file. For personal-grade systems, there won’t be much difference. But for professional- and production-grade machines, the difference can be substantial.

For system setup, find out how long it takes to load (or swap) materials, complete pre-build housecleaning, and warm up the system from a cold start. Results will vary from minutes to hours.

2. Build

This measure gets a bit involved since it will vary with changes in build parameters and by part size/geometry. So measure build time for your typical parts built with the styles you plan to use.

Also consider the difference in time when parts are built individually or grouped together. Some technologies are fastest when many parts are built in a single run.

Process time chart

Investigate the the time needed to clean, prepare and finish parts.

3. Post-process

Every 3D printer requires a few steps to prepare a part for use. Get an idea of what these steps are and how long they take. Examples include support removal, cleaning, curing, de-powdering and infiltration.

That will get you to the basic level of part quality. With an idea of how good parts have to look for your application, also investigate the time needed for sanding, filling, priming, coating or painting.

4. Manual vs. automatic

For each of the time elements, break them down to manual (labor required) and automated (no touch) processes. Then consider what’s most important in your operations. A fast process may need two hours of direct labor while a slower process may only need five minutes. If you don’t have staffing resources, you may opt for a slower process that needs less labor.

Cost

Make a selection based on system price alone, and you could be in for some unpleasant surprises. Get a handle on the total startup cost as well as the ongoing cost of operation.

5. System, peripherals & incidentals

Start with the base price for the 3D printer then add these items to it:

  • Front-end: PCs, third party software
  • System: stands (personal-class), material licenses, upgrades, add-ons
  • Post-processing: cleaning, curing, de-powdering, support removal devices
  • Finishing/benching: workstations, hand-tools, supplies, vent hoods
  • Training
  • Warranty/maintenance: extension for first, full year

6. Facilities

While personal-class systems may only need a 110 Volt outlet, bigger systems usually require modifications to your facilities. Here are some of the items to consider:

  • Utilities: electrical, water, gas
  • HVAC: humidity and temperature control,  ventilation
  • Noise/vibration: dampening or isolation
  • Lab: enclosed/contained room

7. Maintenance

There are two components for maintenance: annual service contracts and routine maintenance.

For the service contract, determine the cost and what it offers. Does it include repairs, preventative maintenance, telephone support and application support?

For routine maintenance, ask what is needed on a daily, weekly and monthly basis. Determine how much time it will take and what tools or supplies are needed. 

8. Materials

Fail to understand the total cost of materials, and you may find that the budget keepers limit the use of your nifty 3D printer.

Cost per pound (or cubic inch) has always been point of contention with users. Relative to commodity and production materials, 3D printing materials are expensive. But the price per pound may fall far short of the net cost. This is because of waste — material that goes into the build but not into the part.

To truly understand this cost, get the numbers for all materials that go into building the sample parts used for the time studies. This will be your effective material cost (total cost of materials ÷ part volume). For example, you may discover that a material costs less than $1.00/in3 but has an effective cost of more than $15.00/in3.

9. Consumables

There are many different types of consumable in the 3D printer industry. Some examples are: build trays, lasers, print heads, light bulbs and nozzles. For heavily used systems, these costs can add up.

Quality

A fast and affordable 3D printer won’t do you much good if the part quality doesn’t match application requirements. Investigate these basic elements of 3D printer quality.

Process time chart

3D printers offer surface finishes from smooth and glossy to rough and textured.

10. Surface finish

Layer thickness and the core process combine to control the smoothness of 3D printed parts. While any part can be benched to a desired finish, your goal should be achieving an acceptable finish without sanding, grinding or machining.

Ask to see parts made with the build parameters you intend to use—time  and surface finish are often at odds— and in an unfinished state. And remember that many of the pretty parts you see on websites and at tradeshows aren’t straight from the machine.

11. Resolution

Resolution dictates the smallest feature that can be made. Over the height of the part, the resolution is a function of the layer thickness. This may differ quite a bit from the XY resolution. In some cases, XY resolution is user-definable. If true, confirm that the resolution demonstrated is achieve with the build parameters (and time estimates) that you want.

12. Accuracy

Accuracy claims are a staple of any system spec sheet. They are also very misleading.

Accuracy is a function of material, build parameters, part geometry and part size. So evaluate accuracy using your typical parts and the intended build styles. If you have access to 3D scanning equipment, use it. CMMs (coordinate measuring machines) may not reflect the true quality. To see the accuracy, use 3D scanning’s best-fit and color-mapping tools to present a visual display of the tolerance across the entire part.

Color map

3D scanning color map shows areas with good accuracy (green).

13. Repeatability

Repeatable accuracy is a whole other story. For parts built in large quantities, investigate the variance of dimensional tolerance for three conditions:

  • Part-to-part: same build but in different locations
  • Build-to-build: same system but over multiple builds
  • System-to-system: same job but run on different machines

14. Stability

If your parts will have a service life of more than a few days, consider the effects of time and environmental exposure. Dimensional accuracy and material properties may change over time when parts are exposed to UV light, heat and moisture.

Operation

You will want to match 3D printer operations to your company’s workflow, procedures, staffing resources and safety codes.

15. Staffing

Evaluate 3D printer operations in the context of decentralized, self-serve production or centralized, technician-run processes. Although there are some 3D printers that can work in either mode, most will cater to one method over the other. If staffing with a technician, consider the demands of the process to determine if he will be a dedicated operator or multi-tasking resource.

Also, consider the labor demands for the post-processing efforts and determine if you have available resources or the budget to hire a staff.

16. Environment

Where do you intend to place the 3D printer— in the office, in a lab or on the shop floor? Investigate the technology to determine if it is compatible.

Independent of the 3D printer’s location, you will need to find some shop space if you intend to bench parts to pattern quality or production-grade finish.

17. Harmful materials

Consider your organizations safety standards (and local codes) for storage, handling, and disposal of materials used in 3D printing, post-processing and part benching. Resins and powders may require special procedures. The same may be true for the agents used to clean parts and remove supports. While many of the materials can be found in the home, special precautions may still be needed.

Evaluate your 3D printer options on these 17 items and let your inner engineer emerge. Create a weighted matrix that emphasizes the importance of each in your operation and drop in your benchmark results. You will now have a very clear picture of the attributes, strengths and limitations of your 3D printer candidates.

For more insight on 3D printer selection, read Evaluating Your 3D Printing Options: Advice from the Experts.

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