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LS Tolerancing 328812380

In our last blog post, we introduced six drivers of CNC machining time and cost. Kicking off this series, we turn our attention to dimensional tolerances. When overly tight, tolerances can easily drive up production time, lead you into more costly machining territory and reduce your yields.

That’s why it’s always a good idea to ask yourself if a part really needs the tightest of tolerances from a functional standpoint. If the part does, then we’re equipped to handle even the most demanding of tolerances. But if it doesn’t, then loosening the tolerances where appropriate can drastically improve the part’s machinability in terms of time and cost—a concept known as design for manufacturability (DFM).

Pay Attention to the Details

Tolerances refer to the acceptable amount of dimensional variation that will still allow an object to function correctly. They can apply to the nature of a part’s form, whether flat, straight or circular, or to location, whether symmetry or concentricity. Other types of tolerances include feature orientation, profile and runout.

The drawbacks of overly tight tolerances boil down to time and cost. For example, at a certain dimensional threshold, hole sizes will require custom or specialized tools, adding cost. Or the machine shop may have to switch from machining, to electrical discharge machining (EDM), jig boring or water jet cutting to hit the tightest hole size specifications, adding time and skilled labor costs.

Even if the tolerances are dialed in functionally, the manufacturing process itself can introduce challenges, leading to low yields and additional costs. For example, it's not uncommon for a machined part to meet tolerance on the warm shop floor, but cooler temperatures during inspection can throw the part out of tolerance.

A Few Real-World Examples

One example of a part with overly tight tolerances is a spider pack, which is part of a rod cluster control assembly for nuclear power plants. This component consists of 24 legs, each of which features a hole with a dimensional tolerance of 0.280 inch—plus or minus half a thousandth. To put these numbers into perspective, the spider pack must include tolerances that are 8 times tighter than a strand of human hair.

Even if one tolerance is off by a tenth of an inch, the part must be scrapped. Making matters even more challenging, the spider pack consists of 24 holes, leading to very high scrap rates and inconsistent delivery times—both of which significantly drive up manufacturing costs.

In a second example, we recently machined an aerospace component that will be sent to the moon. To reduce weight, we were tasked with cutting out pockets with a tolerance of plus or minus 5 millimeters. Bear in mind, these pockets served no other functional purpose than to reduce overall part weight, begging the question: why pay more for such tight tolerances?

Your Key Takeaways

It’s always a good idea to ask yourself if a part’s tolerances need to be so tight. Many down-the-line manufacturing issues related to tolerancing can be easily avoided if addressed during the initial design phase. In many cases, taking the part back to engineering once it already hits the shop floor will prove too costly an endeavor.

Dialing in tolerances is just one of the many ways we can fine-tune part designs for efficient machining. Be on the lookout for our next blog post in this series, which will further explore this concept. In the meantime, sign up for our newsletter.

 


Fine-Tune Parts for Efficient CNC Machining

While a part’s design may meet all the right functional requirements, that doesn’t mean the design is suited for cost-effective CNC machining. In fact, some part features may be difficult or even impossible to machine as designed, which drives cost, quality and yield problems.

In a new series of blog posts, we’ll present some real-world examples of how we fine-tune part design for efficient machining—a practice known as design for manufacturability (DFM). The posts will identify six key drivers of machining time and cost:

  • Tolerancing. It’s easy to specify overly tight dimensional tolerances, increasing production time, reducing yields and driving up costs.
  • Feature sizes. You’ll want to make sure your part features can be manufactured using standard, rather than custom, tools.
  • Surface finish. Designing parts with a finer surface finish than what you need will lead to costly, inefficient CNC production.
  • Radius, chamfers, crossholes and deburring. How your part’s edges are broken around holes and other features affects cost—making part radii, chamfers and crossholes important variables to consider during the design process.
  • Contours. Just because a part can have many contours doesn’t mean it should. Simplifying a part so that it can be made using a three-axis machine, rather than a five-axis machine, will put money back into your pocket during production.
  • Inspection. It pays to tweak part designs to facilitate inspection processes—making this variable an important, yet subtle part of the design process.

At L&S, we can identify these cost and time drivers during the design review process. Our technical team is ready to help you make small adjustments, ensuring your part conforms to standard machinability guidelines without affecting its functional performance.

Be on the lookout for our next blog post, which will continue this series on DFM and delve deeper into our first topic. In the meantime, sign up for our newsletter.

 


Helping Local Students Experience Manufacturing With Fun, Hands-On Learning

At L&S, we've long been dedicated to working with local organizations to teach high school and college students about manufacturing as a way to stimulate their interest—and give them a glimpse of some great career opportunities. Before lockdown, we hosted two projects where students visited our Latrobe facility, watched our machine tools in action and learned about basic manufacturing processes in an interactive, hands-on way.

Students Explore Manufacturing in Their Backyard

First, a group of students from a high school in southwestern Pennsylvania visited our machine shop as part of Catalyst Connection—an economic development organization that provides services, partnerships and opportunities in manufacturing throughout the region. The students enjoyed how "green and clean" our shop was and appreciated the opportunity to learn more about welding, deburring, stamping and several other manufacturing processes taking place in their backyard.

A Probability and Statistics Field Trip

Then in March, a group of nine students enrolled in a probability and statistics class took a field trip to our facility as part of Catalyst Connection's Manufacturing Innovation Challenge. In addition to taking a tour of our plant, the students were assigned to various manufacturing processes, including waterjet cutting, CNC machining and 3D printing.

After their visit, the students worked on and presented a project based on statistical process control (SPC) and statistical quality control (SQC)—two advanced manufacturing tools related to dimensional tolerances that enable us to meet our customers' high expectations for product quality. By calculating the standard deviations for various parts, the students were able to calculate which part, and by extension which process, was the most precise.

To learn more about our precision machining capabilities, please visit our website. You can also read more about SPC in our white paper.

Just about every manufacturing business has a 3D printer nowadays. We’re one of them, and our 3D printer has improved our ability to make, inspect and handle parts for the nuclear, aerospace and medical industries. Here’s how we use it:

  • Visual Aid For Quoting. Our use of 3D printing starts before we’ve even won the job, and we increasingly print components to help us quote jobs. The physical component acts as a visual aid that helps us identify any geometric features that might make a part more difficult to machine.
  • Jump Start On Quality. Most of the jobs we run have demanding metrology requirements. Having a physical model of the parts lets our quality team get a head start on programming the coordinate measuring machines and establishing inspection processes for jobs. We can now start the quality work before we’ve even put the job on a CNC machine, ultimately reducing the time it takes us to ship inspected parts.
  • Simple Inspection Gauges. Our 3D printer also gets a workout making simple inspection gauges for our operators. These gauges don’t take the place of micrometers and our formal part acceptance procedures, but they do offer a fast “go-no go” check on important part features such as slots or holes.
  • Custom Manufacturing Aids. 3D printing is a great way to turn out part carriers, trays, separators to keep parts and tools organized and safe. On parts that ship in strict lot sizes or as matched components for assembly, these printed trays keep orders together correctly.

Because we use 3D printing to support inspection tasks, the printing system’s accuracy and its ability to run dimensionally stable polymers were important considerations for us. We ended up with a Raise3D Pro2 Plus. It’s a high-resolution, accurate 3D printer—offering 0.78125 µm positioning resolution on the x-y plane and a 0.01 mm layer thickness. It supports a range of filled and unfilled thermoplastic build materials. And it has a large 12 x 12 x 24-inch build envelop, allowing us to make larger parts and manufacturing aids.

Using 3D printers is just one of the ways we’re applying advanced manufacturing technologies to CNC machining. Subscribe to our monthly newsletter to learn more.

L&S Machine HAAS UMC 1000
Photo credit: Astrobotic Technology, Inc.

L&S is excited to work with Astrobotic Technology—a cutting-edge space robotics company based in Pittsburgh, Pennsylvania. Making the Moon more accessible to universities, non-profits, companies and individuals, Astrobotic provides end-to-end payload delivery to lunar orbit and the lunar surface.

Using our 5-axis CNC machining capabilities, we're helping Astrobotic manufacture a mounting plate for its Moon landers. A flat component with numerous lightweighting holes, the plate doesn't have extremely complex geometry, at least not by our 5-axis standards. But as a commercial space part, it has rigorous inspection and quality control requirements. For instance, we inspect over 500 dimensions on each plate. Our long experience in the nuclear industry puts us in a good position to meet even the most stringent quality control standards.

From Pittsburgh to the Moon

Fifty years after Apollo 11, Astrobotic is bringing America back to the Moon. The company currently has over 30 commercial technology contracts—including $79.5 million from NASA to deliver 11 lunar payloads in 2021 through the Commercial Lunar Payload Services (CLPS) program.

Founded in 2007, the Pittsburgh-based company offers a variety of payload delivery options, including deployment in lunar orbit or on the lunar surface via landers and rovers. Astrobotic also develops advanced space robotics capabilities, including computing systems, terrain relative navigation and mobile robotics for lunar surface operations.

As Astrobotic's operations continue to expand to new heights, the company will be adding dozens of high-tech jobs to the Pittsburgh area, solidifying the city's role as an advanced technological hub.

To learn more about Astrobotic, check out astrobotic.com. To learn more about our 5-axis CNC machining capabilities, please visit: lsmachineco.com/resources/videos.

L&S Machine HAAS UMC 1000

Our facilities have been undergoing a transformation, and the biggest change has been a move to replace all of our 3-axis machines with new Haas 5-axis CNC machines. While we still have a handful of 3-axis machines for very simple jobs, the bulk of our production milling jobs now go on 5-axis machines. Here’s why:

Streamlined machine operations. The beauty of 5-axis machining is that it can create complex parts in fewer setups. With five axes at the spindle's disposal, the first operation can cut up to five of a given part's six sides, picking up the remaining side with a second operation. The reduction in setups applies to many part geometries—even those that traditionally would go on 3-axis machines. In general, reducing setups not only saves time and cost compared to 3-axis machining but also reduces the potential for errors and scrap.

Standardization. While our headquarters is located in Latrobe, Pennsylvania, we also have a second location in a nearby Pennsylvania town and a third in San Jose, California. By running all equivalent jobs on the same model of 5-axis Haas CNC, we can easily move jobs within and between locations—by simply transferring G-code. This ability allows us to schedule our production operations more efficiently, not just in one plant but across all three.

Training benefits. It's true that 5-axis machines do require some additional know-how for proper use, which increases our training requirements for new operators. However, since we only run 5-axis machines from Haas and have a single control platform, we only have to train operators on one type of machine. All of our operators can run anything on the shop floor. Switching to 5-axis exclusively has resulted in a net reduction in our training costs from the days when we ran a mixed 3- and 5-axis environment.

To learn more about the benefits of our 5-axis CNC machines, watch our plant tour video.


We’re proud to announce that Lauren Morlacci, our Continuous Improvement Manager, was recently named one of the National Tooling and Machining Association (NTMA)’s 30 Under 30 honorees. She, along with 29 of her peers, will be recognized at the upcoming NTMA Fall Conference for her work in manufacturing.

Let’s learn more about Lauren—including her contributions to L&S. 

About Lauren
Lauren was drawn to manufacturing because of her high school calculus teacher, who was also a former engineer. Due to Lauren’s success in and love for the class, she decided to major in Industrial Engineering at the University of Pittsburgh. 

A New SPC Approach
Before receiving her degree, Lauren interned at L&S after her junior year. For her senior project, she helped upgrade our approach to statistical process control (SPC)—allowing us to identify out-of-tolerance conditions before they happen.

This system is currently set up to notify our industrial engineering team whenever a process starts to trend out of control—even if the process is still producing in-tolerance parts. Though launched in mid-2016, this new approach has already improved our machining processes.

You can read the white paper based on Lauren’s senior project here.  

Improvements on the Shop Floor
Lauren joined L&S full-time in 2016. In her current role as Continuous Improvement Manager, she looks for new ways to improve our in-house tools and machinery.

“I work with a variety of technologies—from 3D printers to robotics,” Lauren says. “Recently, I 3D-printed tray holders for our tool collets because workers were frustrated that the parts were too disorganized. These new tray holders save them a lot of time.”

Lauren also manages a team of mechanical engineer interns. Together, they’ve made a variety of improvements on the shop floor—from ensuring consistent tightness in torque wrenches, to designing turntables for sand-blasted parts.

“In high school and college, I didn't know anything about manufacturing,” Lauren says. “People assume it’s loud and dirty—a ‘man’s’ field. But that’s not the case at all. Now, it’s really rewarding to see the results of my projects around the shop.”

You can learn more about Lauren and her fellow 30 Under 30 honorees here.

Learn More

An update on data-driven CNC machining at L&S Machine Company

Statistical process control (SPC) has been one of our most valuable advanced manufacturing tools. We apply traditional SPC techniques to every part we make for the nuclear, medical and aerospace industries. Every year, we generate roughly a million new SPC data points and thousands of control charts, which we use to meet our customers' high expectations for quality.

For all the benefits of our existing SPC program, however, we believe we have barely scratched the surface of what’s possible. In the past, our control charts played a descriptive role, helping us diagnose the root cause of a defect only after it happens. But we have not made the jump to a truly predictive SPC system that flags discrepancies before they happen—until now.

To learn more about how our traditional SPC methods are evolving, download our new white paper, Predictive Statistical Process Control.

Download The White Paper

Predictive Statistical Process Control

 

Check out our new video to learn more about our full range of capabilities including CNC machining, 5-axis machining, welding, water jet cutting and quality systems. Only takes a minute.

 

L&S Facility

If you’re involved in any type of manufacturing, you’ve probably given some thought to what the factory of the future will look like. How automated will it be? Will the machines have more advanced capabilities? And what human skills will be needed to run those machines?

We’ve spent the better part of the last decade grappling with these questions as they apply to CNC machining. And we have not only come up with some answers but also started running tomorrow’s machine shop today. You can take a quick virtual tour of our plant, and you’ll see that it bears little resemblance to an old-school machine shop. You’ll see only modern machine tools in an immaculate, well-lit, healthful working environment. But it’s what you can’t see that will give you the best indication of where machining is heading in the future. These “invisible” factors include:

  • Big data on the shop floor. Many advanced machining operations, including ours, collect and analyze process control and quality data from networked CNC machines. At L&S, we’re collecting more than a million data points every year. Traditionally, SPC and SQC data has been used in more or less a descriptive fashion—to indicate whether a machining process is under control. Recently, we’ve made the jump to true predictive analytics, using our shop floor data to avoid problems before they happen. Look for this trend toward predictive analytics to intensify in the machine shop of the future.
  • Advanced manufacturing capabilities. Good machine shops have always known how to make parts efficiently and to exacting quality standards. Don’t expect that to change in the factory of the future. What will change, however, are the ways that parts are made. Advanced manufacturing technologies—such as waterjet cutting, five-axis CNC, laser machining and additive processes—are picking up steam. The machine shop of the future will have to apply the same process knowledge to these advanced technologies that they have long applied to traditional manufacturing operations. With our waterjet cutter and lineup of 5-axis CNC machines, we’re already using advanced manufacturing systems every day, and we expect to use them even more in the future.
  • The right workforce. Having the right people on your shop floor matters more and more. That might sound counterintuitive given the growing level of automation in machine shops and other factories. But the ability to attract, train and deploy workers with the right skills to run automated processes has already emerged as one of the biggest hurdles for old-school manufacturers. At L&S, we’ve launched novel recruitment and training methods to make sure we have the talent we need today—and tomorrow.

In coming blog posts, we’ll go into more detail about the technologies and human factors that will define the machine shop of the future. We’ll cover some of the steps we’ve already taken and reveal some of the new systems we’re working on. Check back often for new posts or sign up for our newsletter to receive updates by email.  

In upcoming posts, we’ll provide technical tips related to CNC machining, waterjet cutting and welding. We’ll also write regularly about quality assurance, process control, design-for-manufacturability and other advanced manufacturing topics. If you design or buy machined parts, this blog is for you.

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