Posts tagged with construction
Thorlabs and Newport have offered 3D models of their products for a long time. However, they’re typically in formats for expensive programs like SolidWorks and AutoCAD. In the past year or two, Newport has been slowly adding to their library of Google SketchUp models.
I still prefer SolidWorks, but I’m optimistic that I’ll eventually switch to SketchUp. Regardless, it’s nice to see a company supporting free tools.
Fun fact for the day: ThorLabs’ SM2 lens tube standard screws right onto the front end of Nikon’s SLR lenses. Other manufacturers probably use the same threading, I just haven’t tried them.
I don’t know if this is by design or not, but it makes coupling 35mm SLR lenses into optical setups fairly straightforward. I’m using it for a tandem lens macroscope. In the picture above I used ThorLabs part SM3A2. BTW, they also sell some F-mount adapters for connecting to the other side of the lens.
The vast majority of the time, I buy what I intend to. Like the old maxim from construction: “Measure twice, cut once”, I always take care to ensure I’m ordering the right thing. At least when things are expensive. When they’re cheap, I’m less careful. Check out the photo above. I thought, “Sure, that’s the bench vice I’m looking for.” It was so inexpensive, that I went ahead and ordered it without much thought.
I don’t know how big that vice looks to you, but I was surprised when it arrived. Click through to get the sense of scale…
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I was in Tokyo recently and stopped by my friend Taro Ishikawa’s lab (of TaroTools fame). He and Misa are doing very well. They have exciting work underway and are expanding their lab. Taro’s a resourceful, clever guy and while I was there I saw some more of his handiwork. Instead of buying a Picospritzer (which costs $1500-$3000, the NPI PDES system is less expensive, but still in the 4 digits), Taro hooked a regulator (above) directly to an electric valve (below) and called it a day. The valve is actuated by a TTL pulse, and the regulator sets the pressure. Simple, elegant, saves space, and saves money.
Here are some ideas for project enclosures. The stock enclosures from Mouser, Digikey, and others are generally serviceable, but are rarely the perfect size. In addition, making the required cutouts can be inconvenient. Here are a couple of alternatives.
I’ve done this for several projects. It’s cheap, the cutouts are perfect, and there are many different materials that can be used. The downside is that you get 2D panels that you must fasten together. I often use superglue to put the parts together. I’ve also used magnetic strips for panels that need to be removed often. When the material was thick enough, I used screws. Another option is mounting screws and nuts in slots, pictured blow and briefly detailed here.
Here’s an online tutorial example from Rich Decibels (via).
This method offers a way to use screws even when the material is thin. I’m not a big fan of it though, because there are a lot of screws that can easily get loose. Superglue or properly tapped screws are more heavy duty.
Protocase will make completely custom, sheet metal enclosures with cutouts, painting, and silkscreening. It’s a lot more expensive than laser cutting plastic pieces, but there’s less assembly to be done and they’re more durable. They can make all sorts of shapes, including very nice rackmount chassis.
When I’m in a tight spot and don’t have CAD software handy, there are a couple of sites I use to view CAD files online.
ShareCAD lets you upload CAD files in a lot of different formats and displays the 3D model. It offers very minimal interaction, but you can pan and zoom. You also get a link that you can share via email with collaborators so that they can view and download the file. Handy.
ProfiCAD’s AutoCAD Viewer is more limited, but sometimes works where ShareCAD doesn’t. For example, here is an AutoCAD drawing that ShareCAD couldn’t handle.
In the past year, since Labrigger’s first post on 3D printing (aka rapid prototyping), the industry has matured dramatically. Most importantly, companies including Shapeways and Ponoko, have opened what used to be a specialist market, up to more mainstream customers, including hobbyists and small operations.
Sculpteo is a new addition. It is tightly linked with 3Dvia, which offers free software for 3D design and an online design sharing system.
With affordable rates, lots of material options (including metal, pictured above), and decent turnaround times, there’s a lot going for this technology. That said, I wouldn’t recommend getting your own machine. You’re not going to save a ton of time in turn around, all the maintenance and troubleshooting has to be done in house, and you’ll never have as many material options and process options as you can get from a 3D print shop.
3D printing offers very little in terms of economy of scale. This encourages customization, but sometimes you might want 1000 identical parts and not have to pay $20 for each little plastic part. Especially when those parts are disposable or consumable. In that case, limited run injection molding might be the ticket (after you settle on a final design, using 3D printed prototypes). Protomold does production runs from 10-10,000 and prices start around $1500. Turnaround is about 3 weeks.
In the early days of patch clamp electrophysiology, everyone made their own patch clamp amplifiers because there were none commercially available. I was lucky enough to be educated by scientists of such lineage, and in one of my classes, as an exercise, we built a simple patch clamp amplifier with series resistance compensation.
Even after patch clamp amplifiers became commercialized, there were still a few aficionados who insisted on their own designs. But very quickly, companies started building so much technology into the amplifiers, that the amps surpassed what an aficionado could practically engineer in their own labs. Although expensive, the amps were affordable and offered a great deal of functionality.
Perhaps 2-photon laser scanning microscopes (2pLSMs) are approaching a similar turning point. With the expiration of the patent on 2pLSM and the flood of commercial interests in the market, including open source designs like the Janelia Farm scope pictured above (link), we are starting to see much more technology being built into these scopes.
Features such as high speed scanning and wavefront shaping are becoming commonplace. Although both of these can easily be implemented on custom built scopes, the pace of “featurization” of scopes is picking up. Perhaps in five to ten years, no one will be building their own scopes anymore because companies are selling such high tech scopes at very competitive prices.
This website is about open solutions for science, but this is primarily motivated by efficiency, i.e., not reinventing the wheel. We’ll keep covering custom 2pLSM information, for now, but only as long as it is practical. We do not anticipate covering how to build a custom patch clamp amplifier, but it could happen.
OpenMoCo is short for “Open Motion Control”. The community is focussed on building rigs for moving cameras.
They have great, detailed, accessible articles on different topics including gearing, motors, and their own software and hardware. They also list several good hardware sources.
It is maybe not a replacement for pipette micromanipulators. However, for stages, microscope platforms, and motorized mechanisms in behavior rigs, this could be a great resource for a custom made solutions.
The have forums too. It’s not the most active community, but it seems to have a steady pace. And perhaps if they broadened their scope a bit, there would be an increase in activity. The infrastructure itself seems very general. Here’s a diagram:
(via)
So you’re feeling pretty good about the rodent virtual reality system (Hölscher et al. 2005) you have up and running. You’ve got it all… the spherical treadmill with motion tracking feeding back into a 3D vector graphics program that projects a first person view onto a spherical screen. It’s a complex system to put together, no doubt. You deserve to feel proud.
Then Lukas Fischer comes along and destroys the grading curve.
Lukas’ blog is a detailed diary of his meticulous design and engineering work as he assembles his mouse VR rig. In addition to narrating the design and fabrication process, he draws raytraces for the optical projection in his CAD illustrations, like so:
His final work resembles the CAD drawings remarkably well.
Theory:
Reality:
He came up with an elegant solution for the spherical treadmill. After an apt dig at over-engineered approaches:
Different techniques have been used in the past to get a good cup for a 20cm or 8in ball. [...] UCL carved it out of a solid block of gold (or so I can only assume given the pricing)
Indeed, UCL’s expensive (about $5700) spherical treadmill, albeit nicely made, is no where near as efficient as Lukas’ solution: a polystyrene sphere inside another, slightly larger, polystyrene hemisphere with air jets. (link, link)
