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Painting & Finishing Tips for your 3D prints

7 Useful Advice on How to Paint 3D Printed Objects

As 3D printing has a popular manufacturing method for craftsmen and hobbyist alike, many first prints disappoint enthusiasts as the model does not come out showroom floor ready. Most displays claiming to be 3D printed, have had a lot of post-production polishing. Having a truly finished product is far from professional exclusive, and the work pays off. Your post-production polishing is only as good as the surface you’re working with. In turn, advice on how to paint 3D printed objects must also focus on how a model is printed, and pre-painting steps.

paint 3D printed objects
Source: The Golden Drops / Virtual Magic

1. Know Your Model, Know Your Material

Not only are certain materials better for malleability or sturdiness, various printing plastics are vastly different on how to paint 3D printed objects. ABS can be smoothed by acetone, while PLA works better with ethyl acetate. Different materials can also react to the first polishing in distinct ways as well. For example, metallic filaments are best left in a tumbler for an average of 12-36 hours. Quality wood filaments can usually be sanded like real wood. ABS is more heat resistant and works great for interlocking parts, PLA won’t warp as much during your print and is more rigid than ABS. Exotic filled filaments will mostly depend on the thermoplastic second ingredient.

costs of 3D printing
Various filament samples

2. Avoid edges

By edges, this refers to how much of your model is in contact with the print bed. This is more of a minor detail as most models can lose a few layers from the bottom during post processing and be fine. If your model is not one of these, then try to reposition your model until you find a way for it to sit with a minimal contact to the print bed.

7 useful #3Dprinting advice on how to paint #3Dprinted objects

 

3. Slow and small

Small and slow print settings will be your friend. A smaller extruder nozzle will result in a finer off-the-printer surface, this is best if you plan on using chemical vapors to smooth your print surface or if you want to preserve intricate details. Another element of cleaner prints is using additional fans that are directed at the print itself just beneath the extruder.

paint 3D printed objects
Printing toolhead with additional cooling fan

4. Adjust For Your Equipment

If you’re using the ZMorph multitool 3D printer or another high-grade printer, additional fans and extensive sanding may not be required. A great example of a lower need for post-process pre-sanding can be found in Victor Pons’s dragon door knocker. Right off the print bed, there wasn’t much need for filler as the printer didn’t leave much of any ridges so he could use bonding paint since the surface was already smooth. It allowed the hobbyist to spend more time going above and beyond. Just goes to show that everything effects how to paint 3D printed objects.

3D Printed Door Knockers
Source: Victor Pons

5. Always Optimize Your Surface and Prime

Once you have vapor treated, sanded, and or coated your model with epoxy or resin, you’re ready to paint. Almost any project should include automotive primer, don’t limit yourself to “3D printing” labeled materials. Acrylics, gesso, automotive paints, and even iron powder can breathe life into your project. Avoid epoxy on 90-degree angles, as it will round sharp details.

6. Plan Ahead

If you’re moving the model by hand, pick a spot on the outside to hold it by and apply paint, primer or epoxy to that area last. Nothing can be more frustrating than ruining hours of work with finger marks or moving layers of paint. If your model allows for you to use a stand, this would be best.

paint 3D printed objects
Source: The Golden Drops / Virtual Magic

7. Don’t Let Your Work Go To Waste

Don’t be afraid to experiment in order to find a paint that will bond well with your primer or the plastic surface. If your model will be handled a lot or needs an extra shine, use automotive clearcoat. Another variable includes primer, satin, gloss, and matte paints for different looks. Once you have a little practice, try weathering techniques like scuffing and dabbing on accent colors only to immediately wipe them away. When possible, use what you have to your advantage, like the natural lines in 3D printing to accent faux wood.

Example printing and post-production process

  • Optimize your model digitally.
  • Change your printer settings for quality rather than speed.
  • 3D print your model.
  • Vapor treat if you can.
  • Apply a filler putty where need be.
  • Sand (raise grain count by 100-150 after each sand).
  • Apply filler primer.
  • Sand.
  • Apply a standard primer or first paint coat.
  • Wet sand.
  • Paint (preferably with an airbrush). When painting multiple colors, use sealing painters tape and go light to dark colors if you need to layer colors.
  • Clearcoat, clearcoat, clearcoat.

Check out the video by 3D Printing Nerd in which he guides you through the entire process.

This is what makes the difference

This list has been crafted from our experience, observing professionals, and well-known enthusiasts to really learn how to paint 3D printed objects without any fluff or methods that are only rumored to work. So practice, practice, practice, your project will thank you for it.

Adjust the chemicals, materials, methods, and repetition as need be for the filament and model you’re working on. Always work with personal safety equipment, and in a well-ventilated area. Though this may seem like a lot of work, it is enjoyable to most to extend their projects after the initial print. As you move along the finishing process you’ll find constant reward as your print comes to smooth, shiny surfaces.

paint 3D printed objects
Cleaning ABS print with acetone

Post processing is the difference between design and a product that stays around for years to come. After a few test runs, you’ll have the skills to bring your models to showroom status. Use these pieces of advice as a modular procedure, as it can change to best fit nearly any project your heart desires.

Additional resources on how to paint 3D printed objects

If you want to explore the topic even further, then you should definitely check the following sources:

  • Top 10 3D Printing Tricks by Commando Designs

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Responding to production pressure with conformal cooling- by Marc Saunders

Mould tool with conformally-cooled inserts produced by additive manufacturing

Responding to production pressure with conformal cooling

Injection moulding allows plastic products to be produced in complex and intricate detail, often in sizeable production runs, with repeatable tolerances and high surface quality.  Mould tools must be designed to perfectly replicate the 3D design in the minimum cycle time.  Cooling of the plastic part as it solidifies within the mould tool is a critical factor, affecting both the cycle time and the quality of the part.

I explored the use of additive manufacturing (AM) to produce efficient mould tooling in my post Conformal-cooled mould tools – how to cut cycle times and boost part quality.  In this post I look at how these techniques have been applied by leading cleaning systems provider Alfred Kärcher GmbH & Co. KG to boost production of one of their best-selling pressure washers.

Image above – Kärcher casing components being removed from their injection mould tools

Before we look at the Kärcher application, let’s recap the principles of conformal cooling and look at the beneficial impact of AM on mould tool design.

Why use AM for conformal cooling of mould tools?

The goal of conformal cooling is to reduce the temperature of the plastic part inside the mould tool quickly and evenly.  The part cannot be removed from the tool until is has cooled sufficiently to detach from its mould.  Any hot spots will delay part release, may lead to warping and sink marks in the part after removal, and may compromise the quality of the component surface.

Cooling is achieved by passing a fluid through channels inside the mould tool so that the heat is conducted out of the plastic part, through the metal tool, and away in the fluid.  The speed and evenness of this cooling effect is driven by how closely the fluid channel tracks the surface of the tool, and the rate at which cooling fluid passes through it.  We also need to ensure that our mould tools are reliable, avoiding dead-spots in the coolant flow where sediment can gather and create blockages.

Image above – conventional cooling channels produced by cross-drilling require additional plugs to avoid dead spots.  The sharp corner also creates turbulence and limits the flow rate of coolant through the channel.

AM gives mould tool designers the freedom to design complex cooling channels that closely follow the component surface, whilst maximising laminar flow and eliminating dead-spots that might otherwise clog up over time.

In conventional moulds we have cross-drilled and plugged cooling channels in limited regions of the part like this:

By contrast, with AM we can design contoured channels that closely follow the surface of the tool like this:

So AM helps us to design tools that not only provide more effective cooling, they are also simpler to manufacture and assemble.

55% reduction in cooling time increases Kärcher’s productivity

Kärcher makes pressure washers that are sold globally, with more than two million of their K2 Basic model leaving the factory in Obersontheim each year (image shown left, courtesy of Kärcher).  The striking bright yellow casing is manufactured in two halves on six injection moulding machines.

The company needed to increase productivity from these moulds to keep up with growing demand.  Using conventional cooling, the total cycle time was 52 seconds, of which 22 seconds was required to cool the part from its melting temperature of 220°C to the de-moulding temperature of 100°C.

The mould tooling for these parts is substantial and complex, comprising a large cavity and numerous cooled inserts.  The original design is shown below.

The original cooling system for the inserts contains several separate cooling circuits as shown in the image below.  A total of 10 litres per minute of cooling water is used.

Thermography of the ejector side of the original mould tool shows the wall temperature at the end of the 22 second cooling cycle.  We can see significant variation in temperature across the mould, with hot spots that may compromise the component as it is removed from the mould:

The first step to speeding things up is to simulate the mould tool behaviour.  In particular, the hotspots need further analysis as they are responsible for the long cooling time.  A simulation of 20 cycles was undertaken, including an analysis of the wall temperature.  The modelled temperatures show good correlation with the thermography.

Now that we have a model of the current cooling design, we can make design changes to improve things, focussing on the hot spots.  In this case, a part of the solution is to add extra conventional cooling channels into the beryllium-copper mould plate on the nozzle side.

Next we develop new AM inserts for the ejector side of the tool, featuring conformal cooling to carry away the excess heat.  The image below shows these additional 4 mm diameter cooling channels applied to the problem regions:

In one region where there was insufficient space to include more cooling channels, Kärcher made improvements to the product design to alleviate the problem.

When we simulate the thermal behaviour with these new cooling systems in place we see significant improvement in the uniformity of temperature across the part, after a much shorter cooling cycle:

These simulated improvements are borne out by the thermal imaging of the new mould after a shortened cooling cycle of just 10 seconds:

The new inserts are made using AM to create the complex channels.  Some are built entirely additively, whereas others are ‘hybrid’ components which build up additive regions on top of machined blanks.  Vacuum-brazed cores from Listemann Technology AG also formed part of the solution.  The new ejector side assembly is shown below:

In Kärcher’s application, cooling time was reduced by 55% from 22 seconds to just 10 seconds.  Combined with further time savings in material feed and handling, the faster cooling helped to increase the production throughput from each tool by 40% from 1,500 to 2,100 parts per day.

Image above – original (left) and new (right) mould tool designs.

Summary

Conformal cooling enables mould tools to operate faster and to produce more consistent parts.  AM boosts this further by optimising heat transfer to make cooling both faster and more even.

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Innovating design and workflow with the Print Pod

TAM-case-study-hero-banner.jpgCorner brackets

Talk to Stephan Adams for a bit and you’ll soon discover that one of his favorite words is “workflow.”

Founder and managing partner of Adamation LLC, Adams is an entrepreneur and micro-manufacturer who’s all about innovation – not only in product design, but in production. He quickly found that Type A Machines had the perfect tool for his latest project – not just to create a novel design for a new product, but to optimize his workflows.

Adams has been operating in 3D printing for four years, creating action figures and objets d’art, as well as licensed collectibles. Several months ago, he and his brother William, director of Microsoft’s LEAP Engineering Acceleration program for expanding the company’s hiring of women and underrepresented minorities, recognized a new application for 3D printing. As part of the program, participants receive a kit, which includes a Windows 10 tablet and a Raspberry Pi device. “We started talking about how we could use 3D printing in that initiative,” says Adams.

Upon beginning the program, trainees receive a packet of instructional materials. Adams suggested loading the content onto the Raspberry Pi to create an interactive textbook, a low-cost alternative to supplying the hundreds of trainees with full computers. He hit upon the idea of 3D printing a housing that required some assembly. “We wanted to create a fun kit, to make it innovative and interactive,” he explains. The brothers’ design consisted of two triangular pieces of Plexiglas, held together with three corner brackets, and a hanger for the user’s tablet; the brackets and hanger are 3D printed.

Faced with producing hundreds of parts, Adams’ manufacturing side kicked in. “We already had a manufacturing facility for 3D color printing,” he says. “We considered buying a couple of single fused-deposition modeling (FDM) machines and stringing them together, but I decided that would take too long. I said, ‘Let’s do it the manufacturing way.’”

Enter Type A Machines

“I liked Type A’s approach – more of a manufacturing approach than a hobbyist approach,” Adams says. The Print Pod would allow him to create many components at a time with consistent, repeatable results.

“We wanted to create tens of parts in hours to fulfill these kits,” says Adams. “We already had an automated workflow for licensed objects, so we basically used that same workflow to work with the Type A Machines.”

An injection molder would consider Adams’ batch size microscopic; a hobbyist would be overwhelmed. But Type A’s Print Pod filled the micromanufacturing niche perfectly, generating prototypes as well as finished product.

Before settling on the final design, the brothers went through four iterations of prototyping, producing 30 pieces (i.e., 10 kits) for each iteration. “We’d prototype parts that we’d put into kits and sell to Microsoft. And then we’d change the design slightly on the next round.”

Trying to do that with injection molding would be astronomically costly, Adams points out. “With injection molding, each of those slight changes would require a new tool costing $30,000-50,000. And you’d end up with the same cost per unit!” The Print Pod, he says, quickly paid for itself a couple times over.

In addition, creating the kit’s three-cornered shape via traditional methods would be difficult and expensive. “3D printing allows you to make shapes that are unusual and innovative, but practical,” says Adams. And the transparent material used for the brackets clearly shows the 3D printed support mesh. “If it were injection molded, you wouldn’t get that webbing,” says Adams. “We wanted to show some of the advantages of 3D printing, rather than trying to hide the fact that the object is 3D printed.”

 

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All About Workflow

There’s also an advantage that relates to Adams’ favorite word. “Type A is making workflow innovation, and that’s valuable to a manufacturer,” he says. By fitting into his existing operations, the Print Pod increased his batch capacity significantly without slowing down production.

“The added value for me is production time, and that’s all about workflow,” says Adams. “You have a Pod system that’s networked together and all managed from a single interface. Now I’m saving time. What I’m interested in is productivity, being able to integrate the machine into a productivity workflow, and ensure repeatability and quality of product. That’s why I chose Type A Machines.”

Stephan

Adams isn’t interested in incremental printer improvements, such as new features or lower cost, which he calls a “race to the bottom.” “The difference between a machine costing $600-800 and one costing $1200 doesn’t matter if it can’t fit into my workflow,” he explains. “I’m amortizing the value of the Pod over time, which is far greater than trying to skimp to get an upfront cost advantage.”

He discovered, too, that the people at Type A Machines are just as supportive of his workflows as their products are.

Adams wanted to generate a certain quantity of product in two shifts: daytime and overnight. He found that prints failing during the day would throw off the night shift. “Either you’d have to stay longer, until the machines with failed prints could catch up so we could start all the machines at one time, or the night build would operate without those machines,” Adams explains.

In addition to decreasing production, the failures disrupted filament-loading procedures. “You want to have regular intervals for changing your filament, and regular intervals of when you pull off your product and then put it back on,” Adams adds.

The Type A engineers first tried replacing the print heads on the machines with failed prints. That helped somewhat. But they weren’t satisfied.

As it turned out, the main problem was the way the part was oriented on the print bed. “I didn’t discover that; they did,” says Adams. “They looked at the part, analyzed it, resliced it, changed the settings. They tested the part on their own machines in their own facility. They gave it back to me. The yield went up, I was able to stay on time, and I got better quality parts. At no charge.

“All I had to say was, ‘I’m not getting good yields,’ and they took it upon themselves to understand my business, fix the yield problem themselves, run it at their own facility, and bring it back to me. And we got great results” says Adams. “Regardless of what was on their product roadmap, they took the time to understand what I was trying to accomplish, and helped fine-tune my workflow and their machines to achieve that goal. Type A Machines provided me the right integrated system to quickly capitalize on a new market opportunity that I would not have pursued by cobbling together other 3D printing solutions.”

Stephan
printpod.png
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University of California Berkley uses Type A Machines Print Pod

Print Pod Powers Prototyping and Production At UC Berkeley

Students learn by doing – and using Type A Machines

Jacobs Hall, Jacobs Institute for Design Innovation, College of Engineering, University of California Berkeley

  • Type A Machines Print Pod
  • Type A Machines Series 1 Pro

At the University of California Berkeley, creativity is a hallmark and a longstanding tradition. Berkeley’s brand-new Jacobs Hall, at the College of Engineering’s Jacobs Institute for Design Innovation, carries on that tradition, serving as a showcase for students’ and practitioners’ ingenuity and vision. The four-story, 24,000-square-foot facility is designed with flexible, open space and equipped with state-of-the-art tools for prototyping, iteration, and fabrication – all geared towards encouraging students and practitioners to experiment, collaborate, and create.

When Jacobs Hall opened its doors for the first time in August 2015, hundreds of guests anxious to see the promise of the new facility flocked to the grand opening. Front and center, and proudly displaying its ability to make innovators’ dreams materialize in three dimensions, was the Print Pod – Type A Machines’ multi-unit, industrial-strength 3D printer. “It was the highlight of the event for all our guests,” says Emily Rice, Director of Programs & Operations at the Jacobs Institute of Design Innovation. “We had more than 500 people come, and most of them were gathered around the machine at any given time.”

The Print Pod, suited for heavy-duty, large-scale manufacturing applications, allows up to six users using different materials to print at the same time – or multiple units can be allocated to the same job, significantly speeding throughput. “We’re delighted that UC Berkeley chose the Type A Print Pod as part of their state-of-the-art prototyping and production facility,” says Espen Sivertsen, CEO of Type A Machines. “Given the high volume of student projects, the Type A Print Pod will enable Berkeley students with tools that not only help them prototype, but also fully produce thousands of parts on demand.”

In addition to the Print Pod, Jacobs Hall also features four Series 1 Pro 3D printers, also from Type A Machines, throughout the building. The smaller, single-unit machines, which feature a cubic foot of build volume and work with a variety of different materials, are used for class projects, as well as individual students’ endeavors.

All you need is a vision – not CAD expertise

Since its opening in summer 2015, Jacobs Hall has been housing more than 20 courses, all serving the Jacobs Institute’s mission of interdisciplinary, team-based, and project-centric learning. Creative minds from all disciplines, not just engineers and professional designers, are welcome here; and, since many are far from experts in CAD or machining, it was important that the 3D printers chosen for the facility be easy to use. Type A Machines printers fit the bill beautifully.

“When we were planning the equipment that would go into Jacobs Hall, we wanted to be sure that we were including some of the amazing 3D printers that anyone can learn to use really quickly,” says Rice. “You can take an art student or an English student who knows nothing about engineering, has no traditional fabrication skills, but has an idea they want to prototype – this is a product that can let them do that quickly.”

But it wasn’t just Type A Machines’ ease of use that attracted the Jacobs Hall faculty and staff. In their quest for the perfect printers, they went through an exhaustive process of research and selection. “We have a lot of resources here at the UC campus, and we have a lot of people with a lot of experience with 3D printers; so, one of the first things we did when we were trying to figure out what printers we wanted for the Jacobs Institute, we started to poll that crowd for their input,” explains Joey Gottbrath, Technical Lab Lead for the Jacobs Institute.

“What really rose to the top was Type A – everybody had a lot of great things to say about the versatility of materials that can be printed in it, the design of the print head itself, and the durability of these new machines,” Gottbrath says. Adds Rice: “We started talking to a bunch of different companies, touring different facilities, learning about the different 3D printers available out there, and Type A seemed just to have all the qualities we were looking for in terms of accessibility for our students, and in terms of excellent support from the company. And they’re just beautiful!”

Gorgeous design, functionality, and an eye to the future

Indeed, any device used in a facility dedicated to design innovation should itself be prime example of great design. Once again, Type A Machines seem made to order. “Type A was a fit here at the Jacobs Institute for a number of reasons, but it has a lot to do with the company itself – we really felt that it was a good match for us,” says Gottbrath. “We’re really excited to have something so cool and innovative right here. I’ve seen from some other manufacturers some designs around rack systems and farms that are very practical, but just the innovation involved in the design of this Pod, it was really attractive to us.”

The Jacobs Institute staff were thrilled with the support they received from Type A Machines, as well. “Type A was really flexible, really communicative in the ordering and purchasing process, and a pleasure to work with,” says Rice. “The team at Type A was totally amazing. We kind of put them through the wringer; we begged them to come to our opening event in a building that just had had power installed, and to get their new Pod system up and running. And they did a fabulous job.”

A final Type A feature that cemented the deal was Type A Machines’ forward-looking design and vision. The printers can be upgraded easily, guaranteeing their future relevance and use. “We know what Type A Machines are about, and we know what we have here, but we’re really excited about the future,” explains Gottbrath. “We really love the idea that the products that these guys make, we can always upgrade to new and exciting things. It seems like the type of company that’s really interested in further innovation, and we can’t wait to apply those here.”

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Using your 3D printer for the good of humanity

In 2013,  I was fortunate to see a video of a young South African boy named Liam who had just received a new prosthetic hand thanks to the work of Richard Van As and Ivan Owen. That one minute video changed my life. Watch it yourself and you’ll see what I mean.

Little Liam was so cute and had so much determination, his perseverance lead to a worldwide movement called e-NABLE. I joined the movement about 5 minutes after watching this video. Now, three plus years later, thousands of children across the world have received free 3D printed prosthetic hands and arms. I have printed and assembled more than 50 hands and two arms and enjoy the best hobby in the world.

 

To learn more check out www.enablingthefuture.org and www.enablecommunityfoundation.org or contact me and I’ll be happy to get you started.