Could Dynamic Molding Be Bigger than 3D Printing?

An impression left in a pin art board by the lower half of a face. (Image courtesy of Eduardo Habkost.)

If you were around in the ‘80s, you’re probably familiar with Pin Art (aka Pinscreen), the executive toy consisting of a surface made from an array of pins which move independently from one another. This design allows users to create three-dimensional relief patterns of any object—though hands and faces were by far the most popular.

This same principle is now being applied by PinPress, a start-up founded by a group of former nanotechnology students developing a dynamic molding machine.

“The idea is that you take a surface and digitize it, rather than make it continuous,” explained PinPress CEO, Asif Khan. “By adjusting the height of each individual pin, it acts almost like a pixel on a TV screen. So you can change the surface topography, change its shape.”

ENGINEERING.com had the chance to get Khan’s insights on this upcoming technology.

Can you give us an overview of the technology in PinPress?

We developed a new type of motor that allows us to make the pins both small and very compressed, very stackable. There are essentially three main components and by dividing the technology in this way, we’re able to shrink each component individually.

The PinPress prototype. (Image courtesy of PinPress.)

The first component is the actuation—it’s a linear motor, very similar to what’s used in bullet trains. The second component is a secondary clamping or locking system that holds the pins in position. The third system is a microfluidic system that we call micro-hydraulics. What we hope to do with this is make a mold that can change its shape for use in manufacturing.

The idea is to move the pins into place and then hold them while we fill a chamber underneath each one with fluid and then cap the surface. By filling it with fluid, we can achieve the force that’s required for manufacturing.

How did PinPress get started?

When I was a student, I was at a talk at the Perimeter Institute about 3D printing materials. It got me thinking: it’d be nice to be able to use different materials for 3D printing, but the mechanism of it is really what counts. It’s slow and there are restrictions on the materials you can use, which doesn’t make it very ideal for a lot of applications.

So I started thinking about how to overcome these challenges. How do we make something that’s both faster than 3D printing and less restricted in materials? I slowly came up with this idea of dynamic molding, so I called up my friend Nick Vardy and explained it to him and he said “Oh, it’s kind of like that toy.”

When he brought that up, I did the logical thing and went out and bought ten of them to play around with and that’s how we started working with the concept. It’s actually a very old concept; the first patent was filed in the 1800s. MIT built something like it, but the cost of its device was about $20 million. That’s why we developed the motor ourselves, so that we can shrink it.

What we’re working on is a very complicated multi-objective problem, where you’re dealing with heat issues, compression issues and force issues and optimize a solution that meets these parameters while still being useful.

We actually all have backgrounds in nanotechnology engineering at the University of Waterloo. That background helped us come up with new ways to shrink the motors. People with our type of background aren’t really looking at manufacturing, which gave us a unique perspective on these types of problems.

What do you see as the primary applications for this technology?

One of the first ones we came up with was die extrusion, where you’re funneling the material into a shape to be extruded. We were initially looking at pulp and paper, cardboard, thin films—very soft materials.

(Image courtesy of PinPress.)

The idea is that you can extrude it at low pressure and low temperature, which is a good initial application for what we’re doing. It’s also only a one-dimension lip, so it’s kind of like a smart valve that uses our motors to adjust the shape of the edge.

Another application we’re looking at is sand casting, where you’re working with expensive materials. We’re also looking at more exotic materials, such as fiber glass, wood or carbon fiber, since you can’t injection mold these materials.

What are the major engineering challenges that you’re facing?

The main challenge is that there are a lot of trade-offs. The more power you use, the more heat there is, the more heat there is, the more you have to deal with cooling. We’re miniaturizing a very complicated system, so we have to deal with those trade-offs. Even if you have a tiny motor, the packaging for it has a big footprint, so we’re trying to spread that packaging throughout the system.

Right now, we’re fleshing out the major components and working with other engineering design firms to finish the other components. We need to get those main components to a point where they’re very reliable and then start integrating them together.

PinPress recently won the fourth annual N100 Startup Competition, securing USD $100,000 from Northumberland CFDC. For more information, visit the PinPress website.