Selecting a 3D Printer

When first setting out to choose a 3D printer you may naturally ask “Which is the best 3D printer?” Fortunately or unfortunately there is no such thing, and realistically the answer is “It depends”.

It depends on what it is that you want to achieve.

The same is true if you were to ask “Which is the best 3D Printing Technology?” the answer is also “It depends”.

It depends on what it is that you want to achieve.

FFM and FDM™ is a process where a plastic filament is liquefied or melted and the print head then layer by layer builds the object.

When first selecting a 3D printer you should thoroughly evaluate what your expectations are and what you expect your printed part to be capable of.

Are you looking at?

  1. Prototypes – to evaluate the design
  2. Functional Prototypes – to evaluate and test the design
  3. Fit and Form – to see how your design fits together
  4. Models – Marketing or Sales models
  5. Low Volume Production
  6. High Volume Production
  7. Production tools – patterns, jigs, fixtures
  8. Medical – approved medical materials
  9. Modelling
  10. Surgical guides
  11. Dental – approved medical materials
  12. Modelling
  13. Surgical Guides

Once you have determined the part application, you can start to evaluate what part criteria matters most

  1. Part strength
  2. Surface finish
  3. Accuracy
  4. Durability
  5. UV resistance
  6. Heat Resistance
  7. Flexibility
  8. Medical approvals

After a clear picture has been established as to what matters with regards to the part features and applications, it is then possible to evaluate 3D printing technologies and devices.

Specifications

As part of any evaluation of machinery once an understanding of the part or performance requirements are established it becomes important to start comparing specifications, and this is an area that causes a lot of concern, with no approved standards that allow you to accurately evaluate manufacturer’s claims as to the performance of their device.

The key specifications that most people consider are:

  1. Layer height or Resolution
  2. Speed
  3. Build Area/Build Size

Layer Height/Resolution

This refers to the height of the bead laid down by the 3D printer; this can be a deceptive specification as claimed minimum height is often a theoretical figure dependent on material quality, melt temperature and print speed. Layer height although sounding important is not the most important criteria as this does not tell you the key factors of accuracy, repeatability, build strength and reliability. In most cases, very few users of 3D printers ever use the finest resolution on their printers.

Speed

You need to consider that an increase in speed on smaller machines can often relate to a decrease in print quality, because it can cause stretching of the bead as it is being laid down and also lead to “skipping” where bead integrity is compromised.

Build Area

Naturally a big build area makes it easier to build larger models. You do need to evaluate whether a part built on the centre of the build area versus the edge of the build area has the same strength and performance characteristics. Especially on printers without heated build envelopes as the temperature of the build tray (if heated) can vary across the build area impacting strength, size and accuracy. It is not hard to split a model and to build it in parts and it may be worthwhile compromising on build area if it gains you better part strength and accuracy.

It must be stressed up front that that there is no one machine that does it all, your decisions will most probably require a compromise somewhere.

I will briefly cover below some differences between personal printers and professional printers and in my next article I will cover the differences between technologies.

My comments are not intended to define which printer is good or bad but rather to ensure that the differences are clearly spelt out allowing you to make an informed choice.

Personal/Hobbyist 3D Printer

Pros

Cons

Lower Cost

Part Mechanical Performance

Lower Material Cost

Quality/Consistency of Part

Experimentation

Material Inconsistency

Often needs assembling

Machine Reliability

The Personal/Hobbyist 3D Printers offer some advantages to an organisation that wants to start using 3D Printers, as it is an inexpensive way to introduce the concept into an organisation without having to go through long Capex approval processes.

We sometimes advocate that companies or team members who are struggling to justify 3D Printers start off on the Hobbyist route. Eventually, the challenges that are often inherent in Personal/Hobbyist 3D Printers will require that these companies upgrade to a Professional FDM 3D Printer.

The limitations that we have seen first-hand and that our customers have expressed to us when upgrading from Personal/Hobbyist 3D Printers are as follows.

  1. Poor mechanical performance of parts
  2. Warping of parts when printing in ABS
  3. Inconsistency of material
  4. Tinkering needed to set 3D Printer up
  5. Lack of reliability
  6. Lack of Soluble Support – (Soluble Support is a Stratasys specific dissolvable support material)
  7. Lack of Service and Technical support
  8. Need to calibrate machine regularly
  9. Need to level build tray
  10. Difference in part accuracy/performance from the centre of the build envelope towards the edges

Professional/Commercial 3D Printer

One of the key differences you would notice when moving to a professional 3D printer is ease of use. These printers are designed to be tools of the trade and as such are designed to work out of the box. Once installed a professional printer will start printing immediately. The printer is configured to work with the correct material, and the user does not need to be concerned with issues like melt temperature of the material, preparing the build tray etc.

What sets these machines apart are:

  1. Reliability
  2. Part Mechanical Performance
  3. Part consistency
  4. Out of the box performance
  5. Heated build chambers – accuracy, no warping
  6. Soluble Support – allowing complex geometries
  7. Tailored software for the printer
  8. Production use 24/7
  9. Local Spares/Service/Support

Conclusion

3D printing offers many benefits for organisations across the complete value chain from design to production, and the key is selecting the right tool.



Source by Dominic Parsonson

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