THE ENGINEERIST: Mitigating Production Risk with Prototypes

Editor’s Note: The Engineerist is a three-part blog series written by Michael Corr, founder of Los Angeles-based manufacturing consulting firm, DuroLabs. This is part one.

Startup companies have limited time and money, and, rightfully so, treat them as precious resources. There is constant pressure to get products out to the market fast, and when cash is limited, there is little margin for mistakes.

As an engineering manager, my responsibility is to ensure that the development processes being used by my team to bring parts to production are reliable, repeatable, and properly mitigate risk. For high-volume production, injection molding is the best option for plastic parts but it can be expensive and time consuming—two factors that can severely impact the success of a product launch if there are mistakes.

Waiting 12 to 16 weeks for first articles off a steel mold can be an eternity for a company pressured to get products into production in a shortened nine-month time frame. Any delays only compound the issue, adding pressure on myself, my team, and the company as a whole.

CAD model

Analysts at Proto Labs prepare CAD models for manufacturing.

Automated Quoting
When I was first introduced to Proto Labs almost 10 years ago, I was impressed with its commitment to leveraging modern technology. Its quoting process was simple and quick due to automated online tools. This allowed me to independently configure part options without having to go back and forth with a sales rep to update quotes and lead times. The automation saves hours, if not days, in evaluating various options. Additionally, the design for manufacturability feedback tools, which automatically highlight problems and areas of concern in the parts, save days to weeks of time and potentially hundreds to thousands of dollars by alleviating the risk of re-spinning due to an erroneous part. Again, with time being a limited commodity and a close watch on development dollars, these attentions to detail were very important to me.

The Case for Milled Prototypes
Prototyping before production is necessary to mitigate this risk but it can potentially cost money and take time to produce parts, so it’s important to choose your prototype runs wisely. One risk-mitigating technique I’ve incorporated into my mechanical engineering team’s process is to always produce a CNC-milled prototype of any part that is identified to be injection molded for production. This seems like trite advice, but I was amazed at how often engineering teams overlook the value of this step. Even 3D printing, another valuable prototyping tool, is often not as effective as a milled part if a move to molding is imminent. The advantage of the milled part is a closer approximation to the final molded material properties—not only in strength but also look, feel, and toughness when handled.

CNC machining

Proto Labs has hundreds of CNC machines, which enable quick-turn milling of functional prototypes and production parts.

I have now built several dozen parts with Proto Labs, so I can attest to the quality and expediency of the parts. In just a few days and not much investment, one can have several milled parts in-hand and ready for evaluation. Proto Labs’ extensive library of material options has also allowed me to select the same exact plastic to be used in the eventual injection-molded parts. This flexibility paired with comparable tolerances and resolution to final injection-molded parts, allows me to reliably use milled prototypes for a full form and fit check. In many cases, I can even use the parts for structural and environmental performance tests, so we can evaluate and make any final tweaks before cutting steel without having to cross our fingers that nothing goes wrong.

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CASE STUDY: Brain-Machine Robotics System May Help Paraplegics Walk Again

Proto Labs is helping researchers at the University of Houston move a science fiction concept to a real-world application that may help paraplegics walk again.

A University of Houston research lab is developing a powered exoskeleton that will be part of a futuristic brain-machine robotics system. Proto Labs is helping by providing custom-machined aluminum-joint housings.

Photo Courtesy: University of Houston

A multidisciplinary research team that includes engineers, neuroscientists, health professionals, and students is working to create, from scratch, a powered wearable robotic device that allows those with lower-limb paralysis from spinal injury, disease, or stroke to regain mobility without a walker or canes.

A sci-fi element lives on in the project, which is taking place at the university’s Laboratory for Noninvasive Brain-Machine Interface Systems. As the lab’s futuristic name suggests, the ultimate goal is to allow users to control the exoskeleton—commanding it to go forward or backward, to turn, sit, or stand—using their thoughts instead of a joystick, switches, or external operator typical of other devices.


Q&A: Rapid Manufacturing Fit for High-Speed Bike Design

Every year, cyclists converge in Battle Mountain, Nevada in pursuit of achieving speed records at the World Human Powered Speed Challenge (WHPSC). The competition is a mix of athletic performance, engineering and a seemingly endless number of variables. This past fall, Teagan Patterson, a Battle Mountain native and high-speed bicyclist, teamed up with Eric Ware and Mark Anderson to design a bicycle capable of capturing the world record — and her lifelong dream. 

Mark and Eric are veterans of the WHPSC having raced in 2009 with their vehicle, the Wedge, and reaching speeds above 70 mph — good for the eighth fastest time in the world and third fastest in American cycling history.

Drawing from their previous success, they worked with Teagan in preparation for the 2015 WHPSC, where they would try for another record.

Eric Ware knew Proto Labs from his day job as a mechanical engineer, so he decided to call us up for some machined parts for the bicycle design. In this Q&A, Ware gives a look behind-the-scenes at his team’s project.

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WEBINAR: Rapid Manufacturing Methods for Plastic Parts

Tony Holtz, Tech Specialist.

You’re invited to join Proto Labs’ live webinar presentation on rapid manufacturing. The free webinar will be hosted by our technical specialist Tony Holtz and last around 45 minutes with a Q+A to follow.

You’ll hear about the different industrial 3D printing, CNC machining and injection molding processes at Proto Labs, and learn which one is best suited for your next project, based on the project’s material requirements, quantities and lead times.

TITLE: Choosing the Right Rapid Manufacturing Method for Plastic Parts

DATE: Thursday, April 21 at 1 p.m. CDT


Unable to attend? Register anyway and we’ll email you the recording afterward!

6 Ways to Cut Machining Costs

The left image illustrates resulting corner radii from milling. Consider adding reliefs to sharp corners (right image) to improve fit.

Machining gets a bit more complex every year, and as a result, it can be challenging to keep pace with the do’s and don’ts of part design. But lowering the cost of machined parts while improving functionality can still be achieved by a few relatively simple adjustments to your part design or material selection.

Small tool diameters add machining time so consider removing text or logos from machined prototypes.

This month’s tip discusses:

  • Machining corner holes
  • Deburring edges
  • Avoiding unnecessary text
  • Keeping an eye on thin features
  • Reducing part complexity
  • Selecting material alternatives