The usual go-to when building a simple robot arm is the ever-pervasive hobby servo. However, these devices are not precise, and are typically jerky and unreliable. They have their advantages, but if strength is not needed a stepper motor would provide much better motion in the same price range.
Those are the lines along which [Bajdi] was thinking when he forked the Mearm project, and adapted it for small stepper motors. First he tried printing out the servo version on thingiverse. It worked, but the parts were not ideal for 3D printing, and he didn’t like the movement.
So he purchased some 28BYJ-48 motors. These are tiny little geared steppers that tend to show up in the odd project. He modified and simplified the files in FreeCAD. With the addition of a CNC shield and an Arduino he had every thing he needed for the upgrade. A servo is now only used for the gripper.
The robot is almost certainly weaker in its payload ability, but as you can see in the before and after videos after the break, it is dramatically smoother and more accurate.
Continue reading “Simple Robot Arm With Steppers Has Pleasingly Smooth Motion”
A Japanese lab is investing some time in the possibilities of a 5-axis 3D printer. They show it printing using five axis as well as doing finish machining on a printed part. We’ve covered parts of why this is the right direction to go for 3D printing in another post.
It looks like they have modified an existing industrial machining center for use with a 3D printing nozzle. This feels like cheating, but it’s the right way to go if you want to start playing with the code early. The machines are intensely accurate and precise. After all, building a five axis machine is a well known science, 3D printing with one opens a whole new field of research.
There isn’t too much to show in the video, other than it’s possible and people are doing it. The Five-axis 3D printing and machining is uninteresting, we have been able to machine plastic for a long time.
However, they show one blue part in which the central axis of the part was printed vertically, but revolute splines along its outer perimeter were printed normal to the surface of the already printed 3D part. Which is certainly not commonly done. Video after the break.
Continue reading “Japanese Lab Builds 5-Axis 3D Printer”
Only about 10% of blind people around the world can read Braille. One primary reason is the high cost of Braille displays. The cost is a result of their complexity and reliability – required to ensure that they are able to handle wear and tear.
[Vijay] has been working since 3 years on a Refreshable Braille Display but has only recently been able to make some substantial progress after teaming up with [Paul D’souza]. During his initial experiments, he used dot matrix printer heads, but the current version uses tiny vibration motors as used in mobile phones. He’s converting rotary motion of the tiny motors in to linear movement for pushing the Braille “cell” pins up and down. The eccentric weight on the vibration motor is replaced with a shaped cam. Continuous rotation of the cam is limited by a stopper, which is part of the 3D printed housing that holds the motors. Another 3D printed part has three cam followers, levers, springs and Braille pins rolled in one piece, to create half a Braille cell. Depending on the cam position, the pins are either pushed up or down. One Braille cell module consists of two cam follower pieces, a housing for six vibration motors, and a cover plate. Multiple modules are chained together to form the display.
The next step would be to work on the electronics – in particular ensuring that he is able to control the motor movement in both directions in a controlled manner. Chime in with your comments if you have any ideas. The 3D design files are available from his Dropbox folder.
Continue reading “Refreshable Braille Display and Braille Keyboard”
MakerBot is not dead, but it is connected to life support waiting for a merciful soul to pull the plug.
This week, MakerBot announced it would lay off its entire manufacturing force, outsourcing the manufacturing of all MakerBot printers to China. A few weeks ago, Stratasys, MakerBot’s parent company, released their 2015 financial reports, noting MakerBot sales revenues have fallen precipitously. The MakerBot brand is now worth far less than the $400 Million Stratasys spent to acquire it. MakerBot is a dead company walking, and it is very doubtful MakerBot will ever be held in the same regard as the heady days of 2010.
How did this happen? The most common explanation of MakerBot’s fall from grace is that Stratasys gutted the engineering and goodwill of the company after acquiring it. While it is true MakerBot saw its biggest problems after the acquisition from Stratasys, the problems started much earlier.
Continue reading “The MakerBot Obituary”
Optical microscopy is over 400 years old, and in that time, it has come a long way. There are many variations of microscopes both in the selection of lenses, lighting, and other tricks to allow an instrument to coax out more information about a sample.
One proven way to increase the resolving power of a microscope is oil immersion. The sample and the lens are placed in oil that is transparent and has a high refractive index. This prevents light from refracting at the air-coverslip interface, improving the microscope’s overall performance.
The University of New South Wales has a lab that uses such a microscope. They use a special (and expensive) chamber to hold down the glass coverslip and contain the oil. The problem? At nearly $400 a pop, the chambers are a constant expense to replace, and they are not flexible enough to handle custom size requirements.
[Ben Goodnow], a first year student at the university, applied his 3D printing and laser cutting know-how to design and build a suitable chamber that costs much less and can be adapted to different projects. In addition to all the design files on GitHub, there’s also a document (PDF) that describes the design iterations and the total cost savings.
Continue reading “3D Printed Microscope Chamber Saves Big Bucks”
I’ve had a few conversations over the years with people about the future of 3D printing. One of the topics that arises frequently is the slicer, the software that turns a 3D model into paths for a 3D printer. I thought it would be a good idea to visualize what slicing, and by extension 3D printing, could be. I’ve always been a proponent of just building something, but sometimes it’s very easy to keep polishing the solution we have now rather than looking for and imagining the solutions that could be. Many of the things I’ll mention have been worked on or solved in one context or another, but not blended into a cohesive package.
I believe that fused deposition modelling (FDM), which is the cheapest and most common technology, can produce parts superior to other production techniques if treated properly. It should be possible to produce parts that handle forces in unique ways such that machining, molding, sintering, and other commonly implemented methods will have a hard time competing with in many applications.
Re-envisioning the slicer is no small task, so I’m going to tackle it in three articles. Part One, here, will cover the improvements yet to be had with the 2D and layer height model of slicing. It is the first and most accessible avenue for improvement in slicing technologies. It will require new software to be written but does not dramatically affect the current construction of 3D printers today. It should translate to every printer currently operating without even a firmware change.
Part Two will involve making mechanical changes to the printer: multiple materials, temperatures, and nozzle sizes at least. The slicer will need to work with the printer’s new capabilities to take full advantage of them.
Finally, in Part Three, we’ll consider adding more axes. A five axis 3D printer with advanced software, differing nozzle geometries, and multi material capabilities will be able to produce parts of significantly reduced weight while incorporating internal features exceeding our current composites in many ways. Five axis paths begin to allow for weaving techniques and advanced “grain” in the layers put down by the 3D printer.
Continue reading “A Look Into the Future of Slicing”
[Bunnie Huang] recently had the opportunity to do a thorough teardown of the new Formlabs Form 2 printer. It’s a long read, so just head over there and immerse yourself in every detail. If you want the cliff notes, though, read this but still go look at all the pretty pictures.
First, it’s a major upgrade with pretty much every component. The CPU is a huge step up, the interface went from monochrome to full color touch screen, the connectivity has been upgraded with WiFi and Ethernet, the optics are much better and safer, the power supply is integrated, there are lots of little improvements that handle things like bed leveling, calibration, resin stirring, pausing jobs, and resin refilling during a print. Bunnie practically gushes at all the features and impressive engineering that went into the Form 2.
You can compare the teardown of the Form 2 to [Bunnie’s] teardown of the Form 1 printer back in 2013.