Richard Wand, Author at MJ Engineering

MJ Engineering Knows 3D Printing!

Richard Wand on September 12, 2019

In addition to their fused deposition modeling (FDM) desktop 3D printer (see 3D Printer Series—Part 1), MJ Engineering also owns a stereolithography apparatus (SLA) desktop 3D printer. The SLA printer from formlabs is used to make parts for test fits and dry runs.

3D printing materials-SLA

The SLA printer uses photosensitive thermoset polymers in liquid form. An ultraviolet (UV) laser beam selectively hardens (cures) the polymer resin, layer-by-layer, through a process called photopolymerization, which creates strong unbreakable bonds. As the part is being built, the build platform rises, lifting the part upward, out of the resin bath.

Is an SLA printer worth it?

Although the FDM printer can make parts that are stronger and more durable, the SLA printer is ideal when high accuracy or a smooth surface finish is desired. The SLA printer excels at tight tolerances, to the tune of plus or minus one thousandth of an inch—10 times more precise than the FDM printer.

3D printing materials-FDM

MJ Engineering’s Markforged FDM desktop 3D printer builds parts using a black thermoplastic filament called “Onyx,” which is primarily used when parts are needed to check form, fit, and function. The Onyx plastic can be reinforced with different continuous fibers, depending on the intention for the part being printed. Some examples of fill materials used with Onyx are:

Fiberglass—basic, cost-effective reinforcement material
High strength, high temperature (HSHT) fiberglass—to maintain strength in high-temperature settings
Carbon fiber—to withstand fatigue and improves stiffness and strength
Kevlar—to endure high impact and high deflection applications

To add the reinforcement material, the 3D printer uses two different nozzles. One nozzle dispenses plastic (Onyx), while a second nozzle dispenses the reinforcement material in the locations specified by the software. Typically, the reinforcement material is internal to the part and is enclosed in plastic.

Putting parts together

If a part fits within the parameters of the printer’s build plate and height restrictions, it can be printed as one piece. Otherwise, it can be bolted or glued. For example, as a test for a machine MJ Engineering is working on, a part like the one pictured here can be printed out of Onyx on the FDM printer in two pieces and then superglued. Once the finalized design is determined, the printed part can be bolted to the actual machine. “We can make sure it works the way we want it to and there are no flukes,” says mechanical engineer JC Kraml, “before we send it to our machine shop and spend 100 times more.”

To discover more methods by which MJ Engineering is using 3D printing to improve its projects, parts, and processes, check out Part 3 of our 3D Printer Series.

MJ Engineering’s New 3D Printer Adds Value Every Day

Richard Wand on September 4, 2019

When you design custom machines like MJ Engineering does, things don’t always go as planned. That’s OK. Their engineers are experts at solving problems and improvising when necessary. Nonetheless, making customer design changes partway into a project can cost weeks on the schedule and thousands of dollars in parts. To reduce such risks and be more responsive, MJ Engineering recently purchased a Markforged desktop 3D printer.

How it works

The fused deposition modeling (FDM) printer heats a thermoplastic filament to its melting point and extrudes it through a nozzle, layer by layer, to create a three–dimensional object. Precisely following a design in a computer program, it can print production-ready parts that are strong, rigid, and durable.

Is having a 3D printer worth it?

“There are great benefits to using these,” says mechanical engineer JC Kraml, one of MJ Engineering’s resident experts at 3D printing. He praises their new printer for helping avoid project bottlenecks, saying, “It’s fantastic at quick fixes and helping move projects along; it’s great to have for that purpose alone.”

A few of the 3D printer’s many applications include:

Rapid prototyping
Concept modeling
Making replacement parts

Kraml recently used the printer to build a prototype part for a speaker installation jig. “It enables us to ‘fail faster,’” he explains, “meaning we can quickly solve problems that may arise during the design or assembly process. And we save time and money because we manufacture parts in–house.”

Before purchasing the FDM printer, MJ Engineering relied heavily on their machine shops to make parts. After getting the part, which would typically take weeks, there was still a chance it wouldn’t work, meaning more expense and more waiting.

“Our new 3D printer allows us to respond rapidly,” says MJ Engineering President Richard Wand. “If a part doesn’t work, or it doesn’t fit the first time, we can tweak the design, reprint it, and have a new part in a matter of hours.”

Despite its advantages, the 3D printer is not going to replace MJ Engineering’s machine shops any time soon. Larger parts and parts that need to be made of metal will still be fabricated elsewhere, at least for now. In the long term, Wand says the new printer will be good for his company.

It will be good for MJ Engineering’s customers, too. In addition to printing prototype and production parts for their own projects, they can print parts for others who may not have enough need or know-how to make a permanent investment in a 3D printer.

Suffice it to say, MJ Engineering’s new FDM 3D printer adds value with every part it prints!

Collaborative Robots in Manufacturing

Richard Wand on August 30, 2019

A collaborative robot, or cobot, is a type of robot intended to physically interact with humans in a shared workspace. These robots are usually designed for a specific task and come in handy when floor space is limited. A truly collaborative robot, like the ones produced by FANUC, Universal, OB7, AUBO Robotics, Omron, and KUKA, can be operated right next to a person without safeguarding.

But be warned. Just because you can operate a robot right next to a person does not mean you should. While a robot itself might be defined as collaborative, its application might not be. For example, if a collaborative robot has a knife on the end of its arm to cut a shape out of a piece of paper, then by code it might not have to be guarded; however, if it is using a knife that is sharp enough to cut someone, it would be dangerous and irresponsible not to put safeguards in place to protect the people around the robot.

MJ Engineering was once asked by a potential client to integrate a cobot that picked up hot plates measuring more than 200°F. The prospective client thought safeguarding was unnecessary because it was a “collaborative robot.” Not willing to compromise on safety, MJ Engineering insisted on adding safeguarding to its project plan, even though it meant losing the project to a lower bidder. You can count on MJ Engineering to always do the right thing—especially when it comes to safety.

Cobot Safety Categories

Richard Wand on August 30, 2019

To make them safer to operate around humans, cobots are designed to exert a controlled amount of force that will not cause injury in the event of a collision with a person. For that reason, cobots are limited in the weights and speeds they can handle. Most collaborative robots on the market today have weight capacities between 6 and 10 kg. FANUC offers a 35-kg capacity cobot.

The International Organization for Standardization (ISO) and American National Standards Institute (ANSI) break down collaborative safety features for robots into the following four types:

Power and Force Limiting—This type of robot can work alongside humans without any additional safety devices.
Hand Guiding—This type of cobot can be used to read forces applied on the robot tool. This application is used for hand guiding or path teaching and can only be used while the robot is performing a particular function. For other functions, it will need to have safeguarding in place.
Safety-Rated Monitored Stop—All movement stops when a human has entered a predetermined safety zone.
Speed and Separation Monitoring—Movement slows as a human enters a predetermined safety zone and eventually stops if the human gets too close. It does not need a worker to give the go-ahead to resume movement.

“Danger, Will Robinson!”

Do not confuse cobots with industrial robots that are integrated with control systems designed to slow down or stop if a person gets too close. Industrial high-speed robots can handle full payload and full movement, and they will go back to full speed as soon as the person moves away. They do not meet the Robotic Industries Association (RIA) code requirements for collaborative robots.

Are Cobots Worth the Cost?

Richard Wand on August 30, 2019

The Robotic Industries Association (RIA) reports that the collaborative robot market is growing quickly. Advances in robotic manufacturing technology are enabling robot workers to be integrated into the labor force with a wide range of new tasks and applications, increasing productivity and efficiency. The robots themselves are relatively inexpensive, making them a more viable solution for small and medium businesses.

However, the upfront costs savings might not make up for the loss of production, with full-scale industrial robots being at least three times faster than cobots. On the other hand, the larger robots do take up more room, which can be a disadvantage in a smaller space.

So it is important to understand your robotic system needs and whether a collaborative robot setup is truly the best fit for your company. Often, it makes more sense to choose a cobot when there is a specific need, such as a setup where a robot fills a container, and a person sitting next to it puts the lid on. That could also be done in a non-collaborative setting, but it would have to pass through a fence, take longer, and use up more floor space.

MJ Engineering can collaborate with you on your collaborative robot needs and make the recommendation that is the best fit for your company, budget, and space.