Sarah Pavis is the Founder and Principal Engineer at Measure Twice Labs, a New York City-based mechanical engineering design and consulting studio.
Sarah, could you let us know about your background and what brought you to 3D printing in the first place?
I’m a consulting mechanical engineer living in New York City. I graduated with a bachelors degree in mechanical engineering from Worcester Polytechnic Institute in 2006. 3D printing wasn’t as prevalent then as it is now. My first job out of school was working on relatively low volume industrial equipment so most of my early work was designing for traditional subtractive manufacturing (lathe, mill, wire EDM).
Nowadays 3D printing is a big part of my job. I print something almost every day. Most of what I print are prototype parts for companies I work for, as well as for my own products that I’m working on.
What was your very first experience with 3D Printing?
My first experience 3D printing was at work. I joined a new company and a big part of my job was prototyping so I had to get good fast. I started by designing a couple of smallholding fixtures for testing assemblies. Basically mocked up some simple blocks with threaded inserts for screws as well as holding clips. We had an in-house Makerbot Replicatior 2. It was a little fussy but a good machine to learn on. After my first couple pieces snapped, I learned pretty quickly that DFM (design for manufacturing) for 3D printing was quite different than traditional subtractive manufacturing in metals and carbides. I was used to uniform strength but had to adapt to figure out part orientation to accommodate for FDM 3D printed plastic being very weak in the Z direction.
Could you explain furthermore what Measure Twice Labs is and the services that you are providing?
I founded Measure Twice Labs to help early-stage hardware companies take the next step in their development process. The hardware development cycle happens in fits and starts, crunch and lull. I help out in those crunch phases to iron out whatever problem they’re having. For some clients, that’s been early stage concepting and design, for other clients, that’s been later stage smoothing out production bottlenecks. I do CAD, 3D printing, physical prototyping with assembly, testing, analysis, documentation, and factory management. The whole mechanical engineering gamut! I also do a little industrial design and electronics engineering but it’s more of a supplement to my mechanical engineering work.
How did you come to build the company?
I built the company partially out of necessity, partially out of happenstance. At one point I was talking to an old acquaintance about looking for new opportunities and he told me he needed help ASAP so a week or two later I was on a plane to visit a factory for him. From there it kind of snowballed from one client to the next. Hardware development has a natural business cycle and consulting allows me to align my work more closely with the flow of that cycle.
To date, what would you say is your greatest achievement in Additive Manufacturing?
There was a project a few years ago where I needed to design a 3D printed waterproofed assembly. I was still pretty new to 3D printing so, even though I could have done that design in my sleep if it was made out of steel on a lathe, I needed to recheck some of my assumptions now that I was designing for 3D printing. Thankfully I was designing those parts for SLS which is very forgiving for undercuts and other complex part geometry. I used SLS nylon impregnated with carbon for strength and had a waterproof coating applied. That way the print wouldn’t absorb water during testing and would stay rigid and dimensionally accurate. I designed sealing surfaces into the 3D print for gasketing and lip seals which I needed to polish by hand and check the coatings to make sure it was a good sealing surface. Because I was going from steel to nylon I knew I couldn’t use traditional gaskets because there’s no way I could apply enough bolting pressure on the nylon, even with the extra strength from the carbon. So I used expanded PTFE gaskets which was more marshmallow-like and could work with the less polished surface of SLS compared to CNC metal. At the end of the day, it all worked under water which I was very pleased with!
Plus one of my current clients is a 3D printing company so I’m helping to design a 3D printer, which is really cool!
Do you have any (fun or not) story about the company or your career to share with us?
For most of the products that I’ve made, I’ve never actually seen a normal person use the product. I started off in factory equipment so that never seemed weird. But I only realized that was the case the first time I saw a real person use one of my products.
At one point I was working on a toy and had made prototypes for a focus group of kids. There was a camera in the session so that I could see how the kids were interacting with it & it was so amazing to watch. I had just 3D printed most of the parts earlier that day and tweaked them and tested them on my own. Now I got to watch as kids played with them, struggled a bit, broke some parts, but ultimately had fun with it.
Have you run into any challenges from being a woman engineer in 3D Printing?
I’ve certainly experienced my fair share of overt sexism as a woman engineer. The sheer number of time I’ve been asked “do you actually use tools? do you get grease under your fingernails?” drives me up the wall. (The answer, of course, is yes.) However, when it comes to 3D printing specifically I’ve usually been pretty respected by my colleagues. Once I was referred to as the 3D printer whisperer by another engineer. They had used my Cura profile to print a similar part to one I had just printed but their part failed and mine came out well. Since almost everything I print needs to be functional I really try to dial in everything on the hardware and software side to make sure I can get high-quality repeatable prints. Plus it never hurts to babysit the first layer to make sure you have good layer height, adhesion, and filament flow.
Anything exciting coming up you’d like us to know about?
I’m working on some cool products that are still in development at the time of writing this. I’m not sure what stage they’ll be at when this is published but you can check me out on Twitter at @spavis to see if the Kickstarter is live.
What is the most impressive or impactful use of 3D printing you’ve seen so far?
For me, 3D printing is usually a means to an end. Almost everything I 3D print is quite utilitarian. I do it for testing or to examine form or function but at the end of the day that idea lives on in another fabrication process like injection molding. 3D printing is a way station for me.
But for cosplayers, 3D printing is an essential component of the final product. They elevate it into art. It’s really cool to see.
What do you consider game-changing technologies in Additive Manufacturing?
Most of what I see as game-changing are process improvements that make additive manufacturing more user-friendly. Things like mesh bed leveling and flexible build plates. The thing that separates expensive machines from cheap machines is how turnkey it is to get high-quality results. Super expensive printers have a lot of thought and care put into the hardware and software so that the printer works for you instead of you working for the printer.
I’m good at 3D printing because I’m a mechanical engineer but you shouldn’t need to be a machinist to have success. For cheaper printers you tend to have to babysit them and fitness them to get good results, as well as work to ensure that the part you’re printing is designed and oriented in such a way to come out successfully. The less you have to think about it & the more you can design the best version of what you want to make the better. Seeing those improvements trickle down into cheaper and cheaper machines is great.
With all open air FDM printers, Z strength is a big issue, especially when trying to print in anything other than PLA. Sometimes I anneal the parts which works great if I don’t need tight dimensional accuracy (the parts tend to grow in Z and shrink in XY) but they’re much stronger. I’m excited to see more enclosed printers with active heated chambers to allow for better Z strength to temper the parts while they’re printing.
What makes the 3D printing industry particularly interesting for you:
- As an engineer?
As an engineer, 3D printing makes me so much faster at my job. There are some projects where I’ve done 10 different prototypes in one week. Being able to quickly test tiny changes is amazing both for the performance of the product as well as de-risking any potential problems that may arise.
Super fast prototyping can be a trap too. Prototyping is fun! One more prototype is only a couple hours of work! But in my job, prototyping is only one phase and at a certain point, I need to freeze feature design and optimize the product for the full-scale production process (injection molding, cast, stamping, CNC).
- As a woman?
3D printing lowers the barrier to entry for creating real physical products, which is awesome for anyone who comes from a background where they traditionally may not have been encouraged to explore engineering (women, people of color, people from poorer families). There are so many 3D printers in schools and libraries that almost anyone can play around with them to see if it’s something that’s fun or valuable for them.
When I was in middle school I didn’t even really know mechanical engineering was a thing. Seeing middle schoolers today 3D printing and building electronics kits is amazing. It makes me excited for how the next 10-20 years will look when more people from all walks of life create amazing things.
What do you think of the 3D printing industry today? And how would you like to see it evolve?
Seeing how fast the industry moves on the hardware side is great.
Formlabs was the first real desktop SLA contender. I still think they’re the market leader in terms of part quality and ease of use but seeing the Moai, Anycubic, and Prusa SL1 enter the market is awesome for users.
At this point the hardware side is evolving rapidly, the bottleneck is on the design side. As an engineer, I’m designing almost everything that I print but I’m not sure how feasible that is for the average person. I wish there were more open software standards for people to be able to share CAD files. STL and STP files are nice but they’re not native interoperable files. If I send someone a TXT or DOC file, they can open that up in any word processor and edit it. There’s nothing remotely close for CAD files. I’d love to see that evolve.
In your opinion, how could we encourage more women to become involved with 3D Printing?
Getting more 3D printers into schools is great but, fundamentally, I don’t think there’s a pipeline problem. Girls seem very excited about 3D printing and similar technologies. I think the pipeline is leaky and underrepresented people drop out of STEM when then encounter bigotry, either overt or microaggressions.
For a long time, I felt like I needed to be “one of the guys” to fit in as an engineer. But that’s corrosive thinking.
If you’re part of any STEM space (school, corporate, community) let people know that they’re accepted for who they are and don’t have to change themselves to be happy and successful.
Favorite 3D tool (could be a software, machine, material…you name it)? Deburring tool. I like to cut chamfers into my parts for lead-ins. It’s usually easier to freehand than to try to model in small chamfers. Plus it’s great from removing brims.
Favorite moment in your day job? The smells. When I take a circular saw to some plywood (woodsy) or start up a PLA print (sweet).
What’s on your 3D Printing wishlist for the next 5 years? I’m shopping around for an SLA printer, hopefully, I’ll get it this year.
Another inspiring woman you’d like us to interview? I don’t know her personally but @AlinaSpoon uses 3D printing for cosplay in a cool way.