Stepper Motors vs Servo Motors

One question we sometimes get relates to our choice to use stepper motors over servos. We’d like to explain our rationale behind that, as well as why we personally prefer stepper motors to their servo counterpart.

I think the biggest advantage for servo systems is its ability to produce higher levels of torque at high RPM whereas stepper motors produce the most torque at low RPM. You might want to look into something similar to propshaft services for more information on what might be able to help. More torque at higher RPM means having a higher degree of certainty of achieving the desired position in high speed movements, i.e. accuracy and repeatability. If you have any more questions about servo motors or just need a repair check out the Servo Motor Repair Experts. In order to achieve potential benefits of closed loop control you must be willing to make some trade-offs:

1) Increased cost

2) More parts and more complicated system (ie more parts that can break)

3) Decreased low end torque and power

Stepper motors on the other hand give time-proven reliability at a lower cost and provide a more robust system with fewer moving and electromechanical parts that can break. Some will point to servo closed loop control as being superior to steppers because it can correct positional errors should they happen. This may be helpful in traditional manufacturing technologies, but I challenge that a great majority of print failures and positional inaccuracies are caused by the 3D printer operators’ (in)ability to anticipate and control the thermodynamics occurring during the additive manufacturing process.

All plastic shrinks as it cools. Parts that warp and curl can become dislodged from the print surface, cause interference with the print head, and result in a loss of positional accuracy. Here are two reasons it does not help to have closed loop servo control: 1) If the part is warped and dimensionally deformed then the part will be scrapped anyway 2) If the part comes loose from the print surface and effectively causes the print head to loose position relative to your part, then your part will be scrapped. In the majority of causes of print failure, servo control has not saved your part.

If the size of the stepper motor is correctly chosen based upon the loads of the system, and appropriate limits are placed on acceleration and velocity, you will have the same reliability as a closed loop system. I have two large CNC mills driven by stepper motors that will drive a 1/2″ EM through steel at amazing rates machining parts to greater than 0.001″ tolerance. Stepper motors – we went to the moon on this technology!

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IMTS 2016 – My Top Picks

Below is Gigamachinist Steve Johnson’s blog on IMTS 2016:

IMTS 2016 – My Top Picks

by Steve Johnson

A few months ago, IKO International, asked re:3D if we would like to showcase Open Gigabot at their booth at International Manufacturing Technology Show (IMTS) 2016 in Chicago. It would feature their linear rail system incorporated into our printer design, and would allow us to showcase our 3D printers among some of the world’s top manufacturing companies. Naturally, re:3D was thrilled to accept the opportunity to display at our first IMTS.

I have been running the machine shop at re:3D for just over a year, so my experience with 3D printing is still rather shallow, but my experience in manufacturing spans almost 25 years. And because I have a passion for mechanical design and manufacturing, IMTS is to me what Santa’s Workshop is to a 6 year old child. So when re:3D asked me to represent our team at IMTS, I was nervous and giddy all at once. Joining me to man our booth would be Jeric, an engineer from our team well versed in 3D printing. (and born around the time I entered the manufacturing industry) I was glad I would have his knowledge base to learn from and lean on during our time presenting Gigabot.

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With only 2 of us at the largest manufacturing show on this big blue marble we call home, it was very difficult to break loose from the re:3D display to visit other booths, and soak up some of the amazing displays being shown throughout the 1.37 million square feet of display space. We might slip out periodically, one at a time, to view a few booths close by, but for booths further away, we would need to arrive a  couple hours before the show opened to the public, so that we could freely view as much as time would allow.

 

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Over the course of 6 days presenting, we were able to meet hundreds of Gigabot admirers, and also meet several other companies who made a big impression on me in some way or another. These were my top 10 favorite booths from IMTS 2016, and why:

 

10) BobCAD-Cam – There are a lot of companies in the CAD/CAM market. Most, are simple CAM packages which aid the user in creating quick code for simple machine operations, and are reasonably inexpensive. A few, such as Autodesk, CATIA, Mastercam, and ProEngineer have gained a reputation as robust software packages capable of handling the most complex modern machine programming toolpaths in multi-axis environments. These companies also charge a premium price for their packages. And then there is BobCad. The best of both worlds. A high functioning CAD/CAM system at a price even a small business owner can easily manage.

Perhaps I am biased, as I use BobCAD version 28 in our shop at re:3D, to program the machines that make each part for every Gigabot 3D printer we sell. But there is no bias in saying that BobCAD has come a long way, and can compete with the big players in the CAD/CAM market at a price that makes the cost of other software packages seem bloated. And it is a standalone software. Create your solids, straight to code output in one software.

The folks at BobCAD had a relatively small booth in comparison to many of their competitors, but what it lacked in floor space, it made up for in content with a great staff of techs giving demos, and plenty of free swag. No nonsense high end results, and priced for everyone. Enough said.

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9) Autodesk – Autodesk is well known in the manufacturing industry as a leader in design software. So it is probably no wonder that they made my top 10. However, I did not pick their booth on the merit of their software, but rather for the content of their presentation. The Autodesk booth was the first thing you saw as you entered the East building from the skybridge. A massive booth among other software companies, Autodesk designed their area as a presentation stage. And it drew in the crowds all week as they did presentation after presentation on every topic you can think of in regard to manufacturing. (The free beer and coffee may have helped as well) But the one presentation that drew me in the most was a speech and Q&A with none other than Titan Gilroy, owner of Titan American MFG. For me, Titan is a true American success story that exemplifies the spirit of manufacturing excellence, and the drive to constantly improve our process. The desire to continually learn and adapt to an ever changing industry. And Titan shares his motivation and knowledge with the world via Youtube, as well as other appearances such as this. Having Titan speak from their booth was, in my opinion, a wise choice to connect to a broad demographic of manufacturers, big to small, and young to old. I made sure to get a signed poster for our team as well.

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8) DMG Mori / Mazak – This one was a split decision. Even before heading to IMTS, I had heard that Mazak had something special on the horizon. And upon arrival, I quickly heard that DMG Mori was also following the same path. So a visit to each booth was a must.

I remember back in 1997 I attended a tool show in Houston where I was first exposed to 3D printing. The concept absolutely blew my mind. But as additive manufacturing began to gain more attention, I heard the rumbling and grumbling of people in my industry doubting its validity in the manufacturing environment. As time passed and the technology expanded, people on the manufacturing floor began to fear that 3D printing was progressing so much that they believed it would end the need for machinists, forcing us into an early retirement, and the end of a career field. So my visit to both the Mazak and DMG Mori booths was a calming to all the fears of the past, as I witnessed the first two machines to meld additive manufacturing with subtractive manufacturing. Each company presented a mill center capable of CNC milling combined with 3D metal printing. These two machines are not eliminating machinists, but instead, redefining machining, just as the CNC machine did to conventional manual machining. Barriers are being broken down, and new possibilities are being realized. Parts that were previously impossible to make are now a reality. Material requirements are being decreased. These two booths excited me about the future of our industry, and I left envisioning what will be possible tomorrow.

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7) Datron – This booth made my list, in spite of my previous bias. I had seen internet postings about this relatively new company, and their milling machines. I quickly formed an uneducated opinion that they were selling snake oil. So, when I visited their booth I was bound and determined to prove to myself that they were selling a toy, not a tool.

I could not have been more wrong. Yes, it hurts a bit to admit I prejudged Datron, but I also feel it is necessary to set the record straight. Here is a new company that took the basics of what a milling machine does, and threw the standard out the window to design something entirely new and fresh. From the 6hp spindle turning 60,000rpms at a feedrate of 866ipm, to the ethanol coolant mister, to the most innovative vacuum chuck I have seen yet, they did not fail to impress me. Add in a huge touch screen control that has no physical keyboard, and a camera based part zero system that makes setups almost instantaneous. Have they created the perfect mill? No. The machines still have a rather short Z stroke, and a very limited tool diameter capability. But what they have created is totally outside the box from traditional mill design. I do think their asking price on these machines is a bit high, but all things considered, I was pleasantly surprised with this company. Way to go Datron. I am now a big fan.

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6) Oak Ridge National Laboratories – When we speak of 3D printing, it is often difficult for people to envision a legitimate use for it. And most people instantly think of the tiny desktop printers that make tiny knick knacks to display. We at re:3D envisioned something bigger. A machine capable of building real world useful items and accessible to the masses. And then there is Oak Ridge National Laboratories. They took that concept to a whole new level. Upon entering their booth my eyes caught not only a Jeep on a completely 3D printed chassis, but a Cobra as well. Both are fully functional full sized vehicles. This was real world implementation of fused filament printing at it’s finest. But then it got better as I saw the office right behind them… which was also 3D printed. Yes, a full sized printed office structure. When you talk about making a big first impression, this should be the litmus for said impression. I am really looking forward to what they do next.

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5) Stratasys – For people involved in additive manufacturing, Stratasys is a household name. They have been making impressive machines for years. Although a bit pricey, they are a solid company with a quality product and great features. At their booth this year, we got a chance to see a new printer utilizing a 4th axis rotary as well as a multi-axis printhead. This platform allows them to print parts without the worry of support material or overhang, and, less importantly, is mesmerizing to watch. Gone is the concept of extruding layers in a single plane.

I am told that they had a printer there that was capable of printing infinite length prints as well. I wish I had seen that and could report on it as well, but I apparently had tunnel vision aimed in on the multi-axis platform the entire time we were in their booth. Sometimes you miss stuff. It is a huge show. Even without seeing that printer, I felt this booth deserved serious props for WOW factor.

4) Fanuc – This one makes the list, not only for the Fanuc booth itself, but also for the massive presence their product had in so many other booths, including the IKO booth we were showing Gigabot in. Yes, if you have been in manufacturing long, you know who Fanuc is. From CNC control systems to robotic arms and delta systems, Fanuc has their hand in everything. Our booth featured a delta style part sorter that used IKO bearings in its assembly. Numerous other booths featured Fanuc robot arms performing various tasks involved with their product. And then there was the Fanuc booth. We witnessed a completely automated production line of mills running swag parts. Robots loading mills for first op, unloading, flipping, and reloading for second op, and then unloading, washing, and delivering parts as a finished product. All aspects of the line were Fanuc products. A fantastic display of the large variety of products they offer. And, of course, I cannot fail to mention the one item that had people talking all week. A massive robotic arm that was holding a brand new Fanuc Yellow Corvette, and manipulating the car all over the back corner of their booth. Yeah, that was a pretty sweet display of dexterity and power.

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3) MachMotion / Solidcam – A teamed up booth much like our own, the Solidcam booth was hosting MachMotion for this show. Solidcam is a machine programming software that runs native in Solidworks, and MachMotion is a control company who has their hands in many projects. For the Solidcam booth, they were showing a MachMotion mill control that ran Solidworks and Solidcam at the control, allowing on floor programming in a design environment. Solidcam was also giving away a pretty nice 4 wheel UTV at their booth, which they refused to draw my name for. But I won’t hold that against them. And MachMotion also had one of their control systems on an engraving machine in another booth that made me geek out for a bit. The MachMotion control allowed us to text the machine from any cellphone, at which point the machine would ask us what text we wanted to engrave. Reply with a line of text, and the machine would process our request by engraving our requested text on an aluminum thumb drive. Custom made swag is always the best swag.

 

2) IKO International – We cannot make this list without giving a shout out to the company who made it possible for us to attend IMTS in the first place. IKO welcomed us into their booth as a display of their linear rail system at work. We shared space with a couple other machines sporting IKO equipment. But the show winner for IKO… the machine that stole the limelight all week long… a simple claw machine built by a couple IKO engineers and salesmen, utilizing IKO ball screw systems. Loaded with IKO swag such as flashlights, notepads, and Rubik’s Cubes, the line to play the IKO claw machine stayed full all week. We may have gotten a bit jealous that it got more visibility than Gigabot, but in reality, we lined up a few times to play as well. Hey, it was fun.

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1) F.I.R.S.T. – For Inspiration and Recognition of Science and Technology – An organization founded by Dean Kamen, had a huge presence on the C hall, and brought in students from 38 states and several countries to be a part of IMTS. This organization also had several activities planned for the students, which helped inspire these young minds to move forward to become the designers and manufacturers who will shape our future. I have to list them as my number 1 pick, as this organization is building our future, and helping our next generation to dream bigger, and reach beyond the stars. Thank you for all that you do.

 

Happy Printing!

steve@re3d.org

 

Making Electric Motorcycle Battery Packs with Farasis Energy

“I got into 3D printing while I was in college doing my electrical engineering degree. One of the things that really got me interested in it was being able to make a box for the electronics projects that wasn’t made out of cardboard and duct tape, which is kind of a trademark of most EE students.”

This is Chase Nachtmann, a Systems Engineer at Farasis Energy.

“That kind of sparked my interest in working with 3D printers, because it’s a way of designing things…and having them come out exactly the way that you want.”

Nachtmann ended up managing the high-end industrial 3D printer at his university, and has now put this knowledge to use post-graduation.

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Farasis, based out of the San Francisco Bay Area, makes lithium ion batteries for electric vehicles. They use Gigabot to print parts for a variety of applications throughout their battery pack development process.

Part of that process involves bolting their pack onto a shake table for testing, which puts it through the ringer by vibrating at a punishing 90 G’s sinusoidal in each direction. This particular piece of equipment is pricey to rent time on.

“It’s very expensive, and it costs a lot per hour,” Nachtmann explains. Jackson Edwards, an Applications Engineer at Farasis, jumps in – “Four hundred and fifty dollars.”

Nachtmann continues, “ When you’re doing a custom-shaped box, at least one hour is just spent bolting it onto the table in a secure fashion.”

This is where their Gigabot comes in.

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“By printing it, we have a custom box that has the mounting holes already integrated into it – we’re saving a lot of money that way – and we’ve found that printing it was definitely strong enough after we filled the inside with an epoxy body compound,” Nachtmann says. “It saved a significant amount compared to having it machined out of aluminum.”

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This machining process was their only option prior to getting a 3D printer. Edwards recounts the process of shopping around for the most affordable option. “We were quoted between two and five thousand dollars for the piece of aluminum, and it also had a 2 week lead time,” he recalls. “Having the ability to make these fixtures in-house is a huge help.”

Contrast this with what it costs them to make the 3D printed version, an extremely dense, 100% infill piece, and it’s a no-brainer. The printed piece uses about five pounds of filament, bringing their cost of printing a custom box to just under $100. On top of that, there’s no lead time: it’s something they can do in-house as needed.

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The Product in Action

One of Farasis’s battery packs’ big applications right now is electric motorcycles.

“We just recently completed a build for Brammo’s Isle of Man motorcycle,” says Edwards. “The bikes performed flawlessly and everything went great.”

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Another notable name on their customer list is Zero, known for their high-performance electric motorcycles.

“They are right in the middle of their build year right now, making 17 bikes a day,” Edwards explains. “Going to a production-level status with them is pretty fun.”

Zero’s bikes use somewhere between 56 and 140 of Farasis’s battery cells, and the Farasis team has also made some 3D printed test fixtures and parts for their validation builds.

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As a true sign of someone in love with their work, Jackson proceeds to wheel out a Zero bike of his own from the back of the office.

“I commute from the Santa Cruz area,” he explains. “I used to commute from Aptos, which was 67 miles one-way…but now I’m a little closer and it’s only a 50 mile trip.”

He explains that the bike has a range that would allow it to do the entire round-trip on one charge, but as he puts it, “it’s nice to have a little bit of headroom.” He opts to plug in at the office while he works.

I get my motorcycle-fantasy fix vicariously, so I leave with the question: how fast does this thing go?

“The fastest I’ve had this one is 105,” Jackson reveals. “It’s a heck of a lot of fun.”

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Architectural Decoration with 3D Printed Molds

The following is a story from Stockholm-based Gigabot owner Monsén Arkitekter

“We feel that contemporary architecture is now too minimalistic and the naked buildings have lost their storytelling aspect. In our latest project, we designed human figures demonstrating the anatomy of movement for the façade of a building. We quickly realized our small office 3D printer was too small for the job, which is when we found Gigabot.

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Artist’s rendering

We have used Gigabot for producing decorative building components in full scale to be used for exterior and interior design. This could be 3D printing molds for concrete casting or using the printed designs directly on the buildings. We use 3D printing for what it is really good at for architecture: making fine details. And it doesn’t stop there. Concrete printing is developing more and more so hopefully at one point we will be able to print whole houses! For more information on this, check out Broowaha.

Everybody said it could not be done, but after a few very entrepreneurial weeks, we got a test plate made. The cost of the plate was 20% of what it would have been had we gone the other route and used a big industrial printer. Four hundred casted plates later, the building with the people on it is the talk of the town in Uppsala, Sweden where it is located.

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Concrete panels cast from 3D prints

We invented a new architectural style which we like to call Super Deco, a fusion between super-modern buildings and 3D printed decorative elements. Gigabot gave us the opportunity to make this a reality and to bring character back into architecture. Our hope is that other architectural firms catch onto Super Deco and start to decorate our cityscapes again.”

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The concrete panels in the real world