3D Printer Shootout – Pro vs. Consumer

A few days ago, Scott Hanselman bought a $599 consumer 3D printer on Amazon. He then went on to share the next 16 hours worth of elation, frustration, moments of success and suicidal thoughts that go along with learning 3D printing on consumer hardware and open source tools.

My experience was even worse than his – as a company, we bought into the idea that $1000 worth of 3D printing machine should immediately bring us into the 3D manufacturing revolution. Months later, walking in to yet another night where the MakerBot printer had freaked out and spewed a massive tangle of spider-webby filament balls all over the floor, I was fully convinced that 3D printing, as an concept and industry, was a complete and useless pile of crap. We got 1 successful part for every 5 tries. We bought every kind of add-on available to heat up build plates, printed fan and enclosure mods, with some magic combination of painter’s tape and AquaNet hair spray being the only things that occasionally worked. Before writing it off altogether, we invested in the next level of equipment that held promise, and now work with a basic, professional-grade printer. We spent way more on payroll for someone to sit around and dink with the printer than we did on buying the professional printer. I made a rule that if anyone ever purchased any printer, part, or accessory from MakerBot ever again they would be immediately terminated. That was 2 years ago.

With that said, I challenged Scott to a Pro vs. Consumer 3D printing shootout – our Stratasys uPrint vs. his Simple Metal, to see the good, the bad, and the ugly of each approach, and find out how we compare on each side of the spectrum. We gave it one shot, no do-overs, using only the printer and the software that came with it, for honest comparison.

This blog post represents our “Pro” side of the experience. Open Scott’s side in another tab and compare.

The Model

We each printed the same model from the same source – a coffee cup .STL from Thingiverse, available here. (For the uninitiated, a .STL file to a 3D printer is more or less like a .PDF to your laserjet office printer.) It’s not a super crazy shape, but at the same time requires a bit of support with curved surfaces – about what the “average” 3D print would be.

The Setup/Costs – Stratasys uPrint SE Pro

This is the bad news on our side – you get what you pay for. Stratasys makes the uPrint SE Pro as one of their entry level, professional grade models. It prints a single color at a time, with a single type of material (ABS). To duplicate our setup for this print, you would need the following:

uPrint SE Pro Printer and Dissolving Bath – about $22,000

1 Spool of Model Material (Black) – $205.00 (produces 42 cubic inches of printing)

1 Spool of Support Material – $200.00 (42 cubic inches worth)

Box of Build Plates – $125.00 for 24 (you need one for each print, so it costs about $5.20/each)

Soluble Concentrate – $149.00 for 12 bottles (dissolves support material, aka fancy drain-O)

Warranty Support – $2,000/year – because it does break from time to time.

Add a little bit of shipping, and for a mere $25K you’re ready to print your very own coffee cup.

Setting Up – Hardware

The good news is, all of our supplies come from the manufacturer of the printer – so the major plus on the “Pro” side is that everything works together.

First, we take a build plate out of the box.

They are plastic and have a texture on them that is magic, because it sticks to 3D material once and cannot be reused. If we are printing something small, then sometimes we can use one corner of the build plate for one print, then another corner later, but it just depends on the day.

The build plate snaps into place on a platform that is extremely solid – Stratasys seems to over-engineer their hardware, which is nice.

Next, printers need material, so we load both the model material (what our print will actually be made of), and the support material (what the printer uses as filler to support overhanging surfaces, and gets dissolved later).

It comes in a “space bag” and gets loaded into a cartridge.

Look closely – you see that little red thing?

That piece acts as a flow-meter for your material spool, and tracks how much material you have left.

Unfortunately, this is what I call the “DRM” of 3D printing. This little module makes sure that you are using a Stratasys material spool, and not material from other vendors. It’s one-way and cannot be “rewound”, so you can sometimes end up with a bit of material left over and the module thinks you’re already done, thus rendering the extra material unusable.

Aside from that, we load the spools, which is a matter of sliding them in and pressing “Load” on the printer panel.

Now we’re ready to do some printing!

I tried to get a great “action shot” timelapse of the print by taping a GoPro to the inside of the door. It’s a little tight in there, so I cut the handle off the build plate to make room for it.

That worked great until the printer heated up, the tape turned to goo and fell off, and the GoPro shut itself down at 125 degrees F. So I had to settle for a GoPro shot outside the door instead.

Setting Up – Software

With this type of printer, you work with Stratays’s “Catalyst” software. Again, everything just works together – no mucking around with config’s and jumping through multiple tools, which is nice.

1. Download the .STL from Thingiverse.
   
2. Add the .STL to Catalyst.
   
3. Press “Auto Orient” and “Add to Pack”, progress bars fly and magic happens. (Really, software is just calculating the most efficient way to print it, where the coffee cup needs supports and so forth.)
   
4. Drag it to position it on the build plate where I want it to print.
5. Send/queue the print to the printer.
6. Hit the blinking “Start Model” button on the printer’s front panel.

Printing

I hit print and walked away. The printer tells me % complete and time remaining (7 hours and 29 minutes) and is also monitored in the Catalyst software.

The printer is very conscious of interrupting airflow, so a magnetic latch engages and prevents us stupid humans from opening the door mid-print, without the software’s permission.

This print ultimately took 8 hours, 22 minutes, at 0.1mm resolution, used 4.84 cubic inches of model material, and 0.433 cubic inches of support material.

Dissolving

Out pops our 3D printed coffee cup!

You can see the model material (in black) and the support material (in white). The white has to disappear, so to do that, we dunk the whole thing in a hot bath.

The bath comes with, and is considered part of the printer. It’s a highly concentrated liquid (resembles Drain-O) mixed with water. We have to change it out every month or so. This unit heats up the liquid, and has a hot-tub style jet inside to keep a continuous flow of water over the part. We use big rubber gloves to prevent contact with this solution on bare skin.

All Done

We lift the container out of the bath, and what remains is our coffee cup and build plate without support material.

A quick rinse, and we’re ready for coffee.

Cost of a Coffee Cup

In direct costs, we used $23.62 in model material, $2.06 in support material, and $5.20 build plate, for a total of $30.88. We have a fancy spreadsheet that calculates our total cost (printer cost over its lifespan, average reusable supplies based on our normal print volume), and our average cost per cubic inch of model printed is about $11.80. So if a customer asked us to print this coffee cup, it would run about $58.00.

On to Scott for the conclusion…

What does the end-result look like in cost/value/process? Was Scott able to print it in one shot without drama, or did 3D printer parts and a tangled mess of open-source bits come flying out of the nearest window in a fit of rage? How close are consumer printers to competing with professional printers in ultimate time and value?

We shipped Scott our version of the coffee cup, and he tallied the final scores. See what he had to say…

Behind the Scenes with the Kinect Train Build

It’s been a little while since the last Christmas project, so it was time to do something again.

This year, I started out with the following criteria for the Christmas for the City display:

• Something interactive
• Something that gets more fun as more people join in
• Something that lets groups of people compete

Concept

The weekend before, my wife came home with a Nestle model train she got at a toy sale for $20:

This was great – trains and Christmas go together, and if the train could be driven by some input, we have the beginning of an interactive display. My plan at this point was to mount a series of industrial buttons, and wire them to a Netduino. The faster more kids pushed buttons, the faster the train would go.

However, I was running a little low on time at this point, so I needed something a little simpler. I was thinking of what might be possible while I was watching TV, and noticed my Kinect sitting under the TV. That was perfect. The more motion in front of the depth camera, the faster the train goes.

Measuring Motion

Using the Kinect library, I wrote a small app that grabbed each camera frame and passed it into an AForge.NET motion detection library. This gave me a motion analysis similar to this picture, where red areas represent “things that have moved in the last second or so”.

By counting the number of “motion pixels” each second, I ended up with what I coined to be the “motion number”. This could be 0 to 150,000 to 600,000 depending on how much motion was happening. I translated this into a percentage based on the max value seen since application start. So now we have a “motion percentage” from 0-100%. This will more or less serve as the value we need for the train throttle.

Mounting the Train

Trains, sensitive electronics, and anything else not bolted down or secured don’t last very long in front of kids, so in order to keep the train from being kicked, shoved, punched, or stolen, it needed some kind of enclosure.

For this I used some Bosch Aluminum Profiles – this stuff is amazing, we use it for just about everything. Our awesome distributor we use at work fabbed/cut pieces for me in a day and then it was off to the assembly area – the area between the couch and the dining room table.

This is also the point where I found out our new puppy hates portable drills..

OK, so one problem.

I set up the Nestle train and… it didn’t work. Either the engine or the controller didn’t work. Still not sure what the issue was, but I had come too far now to abandon this one.

This was Saturday. I had the rest of the night and Sunday to finish this thing. I called The Train Loft in Winston-Salem Saturday evening. They were closing in 15 mins but Jeff stayed late so I could come get another train. They had an amazing display – not something I was going to attempt:

Anyway, Jeff hooked me up with a Polar Express train set, and tricked up the track a little bit with a figure-8 instead of just the oval. Project officially over-budget at that point, but hey, Polar Express and Christmas go together, right?

Controlling the Train Throttle

What I thought was the easy part actually became the hardest. Turns out that train voltage is weird in a lot of ways (this train used AC, not DC), and controlling it via a computer is not that easy. I looked at various options for this, even trying to use an AC dimmer limited in software as to not overload the train. This got risky quickly, so I opted for a more simple mechanical control on the actual train controller. I pulled out the Lego Mindstorm NXT programmable controller and modified the train controller handle to attach to NXT…

The before:

The after:

While it looked cool, the “conveyor track” had a lot of slippage in it. Had to modify it further to couple the servo motor directly to the controller, and then I was in business.

Making it into a Game

So, now I had a “motion percentage” to use as a throttle value, a way to control the train via software, and a mounting rig.

Now, I just had to make it into a game. So I wrote an app with this workflow:

• Plays a Polar Express intro clip with the instructions (“move your body to make the train go”)
• Gives a 3, 2, 1 countdown
• For 30 seconds, enables Kinect, plays a Polar Express theme song while the train runs, displays the “motion percentage” in 0-400mph (yes, not really to scale, but hey…), and displays the “distance traveled” by the train
• After 30 seconds, stop train and display high scores (how far the train went in the 30 seconds)
• Repeat

Deploy!

I wrapped all that up, and our awesome Christmas for the City volunteers helped set up the rig at the convention center. Here are some pics of what it looked like:

Overall, this worked out great. It was a self-contained rig most of the time running one “round” every minute. Kids participated in nearly every round in the 6-hour period during the event. We had groups of kids competing, groups of adults competing, and a few “die-hards” with sweat pouring down their faces, and most of all a ton of smiles.

One of my favorite parts of the night was when one kid came over and played a few rounds, and then went to see Santa across the room and asked him for “a Polar Express dance game just like that one”.

All in all, I think I achieved the initial objectives, and combined some great hardware components together in a short amount of time!