Bob Larson

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Bob Larson last won the day on January 30 2018

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About Bob Larson

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  1. Reposted on behalf of another wpl owner:
  2. From the Internet:
  3. Here are some from pinterest and facebook.
  4. Quick! Modify an STL file — Fusion 360 Tutorial — #LarsLive 118
  5. Fusion 360 — Beginner! How To Pan, Zoom, Rotate & Navigate
  6. How to Solve Extruder Skipping January 18, 2015 wd5gnr If you hear clicking when filament is moving in your printer, it may be that your extruder is skipping. This isn’t always a big issue, but it does upset the flow rate so your prints are probably not as good as they could be if you are skipping. In extreme cases, it can ruin the print and could even damage your extruder. So what causes it? The short answer is that the extruder skips because the stepper motor can’t produce enough torque to move the filament the requested amount over the requested period of time. Practically, though, the question is why does this happen and how do you fix it. There are four basic reasons you might get an extrusion skip: jams, mechanical issues, electrical issues, and software issues. Some of these issues are interrelated so you might divide them up differently than I do. Jams are usually caused by some obstruction in the path of the filament. Sometimes, it is the filament itself getting kinked. Binding in the feed (for example, a tangled spool) is another common cause. Cheap filament may be bulged out. However, there is another source of obstruction: your misaligned bed. If the nozzle gets too tight against the bed, plastic can’t flow, pressure builds up, and skips will occur. If you can hear skipping when the nozzle is not all the way down, this isn’t your problem (or, at least, it isn’t your only problem). If you get skips uniformly on the first layer, but not later, the whole bed may be too high. If you get skips only on the first layer in a certain area, the bed may be tilted (although some printers automatically deal with that). The solution is to clear the jam, where ever it is. If it is bed related, get the bed height correct and flat. If you are extruding at too low of a temperature, the plastic is harder to flow and again you may build up enough pressure to skip. Another possible cause of bulging filament can occur if the plastic gets squashed at the point it is being grabbed. Pretty much all extruders have some kind of gear or hobbed bolt or pinch roller that grabs the plastic and pushes through some kind of hole or tube. If this pinch point is too tight, you can flatten the filament making it too fat to feed. Another possible issue is if the filament is getting hot over time because your hot end isn’t insulated well or your extruder motor is getting hot and the plastic is becoming soft enough to get pinched even though the pinch pressure isn’t very high. Some extruders can even be adjusted so the pinch is too tight for the motor to feed through. If skipping occurs after a long time, you could be getting a soft spot. Mechanically, you can have a few issues. I mentioned that there is usually some kind of pinch mechanism and a path for the filament to flow. All of this stuff has to be aligned pretty closely or you get binding (which is a kind of a jam). Your hot end needs to line up with the other end of that hole or tube, too. One thing that is easy to overlook is the speed of the extruder. If you try to move plastic too fast, the gear may just slip. Printing fast, printing high volumes (e.g., thick layers), or having too high of a setting on E steps can lead to this. I had this problem recently when I switched from a geared extruder to a direct drive one. Even though I recalibrated the extruder for printing, I forgot the same number is in the printer’s default EEPROM settings. Starting the printer up and manually extruding was a disaster, but prints worked well and after a print, the manual extrusion would be ok. The default speed was just too fast for the direct drive extruder to handle (the geared one needed the faster motor turn to get a slower speed through the gear box). Electrically, you need to be sure the servo has the right amount of current flowing. Most printer boards have some way to adjust the servo current. If the servo is cool to the touch after a good print setting and you are skipping, you may need to increase the current. If the servo is very hot after a few minutes of printing you may need to decrease the current. A hot motor can cause skipping, so this is a case of where more is not more and less is not more. Just enough is more. The same holds true for software. You need to have an accurate extruder calibration. Like I mentioned before, spinning too fast will cause the extruder to slip. High acceleration can be the culprit as well. So how can you bundle all this up into a reasonable check list? 1. Start with the head well away from the bed. If you manually extrude filament do you get skipping? If so, check the temperature, the filament path, or the calibration. 2. Notice if the skipping only occurs at certain places consistently. This could be where you bed has “bumps” or (in a case it took me a while to figure out) that the extruder stepper motor cable is intermittent and those locations put stress on the wire in the right way to break the connection. If it skipping mostly on one corner or one side, suspect bed leveling. Level the bed if necessary. Note this doesn’t really mean to get the bed level to the ground. It means the bed must be parallel to the movement of the print head. 3. If you don’t have extrusion on the first layer at all, then almost certainly the Z height is too low. Readjust your Z height. 4. If all else fails, try raising temperature and lowering speeds. Try a different material. Adjust the drive current to the extruder stepper, if necessary.
  7. Nice stretched Jeep JK build. Thanks, goes out to scale builders guild
  10. Microsoft, who last year announced that they’d managed to break the world record and store 200Mb of movies and documents on strands of DNA, the details of which were published in a paper published on Biorxiv, have now announced that they’re going to be the world’s first company to offer DNA storage as a service as part of their Azure cloud offering, and that’s on top of their project to turn Azure into the world’s largest supercomputer, or build the world’s first commercially available quantum computer – something that would perfectly complement a DNA storage system. Furthermore, and this is the really exciting part of it, they plan on doing it by the end of the decade – this decade.
  11. Ever since life gained a foothold on this fragile rock three and a half billion years ago its story has been written in a DNA code consisting of just four letters – G, T, C and A, that all pair up to form the DNA double helix, and the sequence of these letters, up until now, has determined the makeup and characteristics of every organism on Earth – from the earliest sponges and Amonites to the dinosaurs… and us. Over the decades adding, deleting, and splicing genes has become routine, and some researchers are now even designing new DNA to create new creatures, such as E. coli that are resistant to every known virus on Earth. But while many researchers are hard at work rearranging the existing DNA letters into new sequences a new experiment run by the Scripps Research Institute in California has redefined the concept of synthetic biology by creating and writing two new letters. On Monday the team at Scripps, led by Floyd Romesberg announced in a paper published in Nature that they have expanded the genetic alphabet of DNA from four to six with the addition of two new letters, X and Y. And they showed that the new letters could be integrated into the DNA of a living creature, in this case an E. coli bacterium – exponentially increasing the amount of information the genetic code can store, bearing in mind that just a shoebox of existing DNA could be used to store all the world’s information.
  12. Scientists use brain controlled DNA nanobots to release drugs inside roaches Though merely a demonstration and proof of concept the technology represents a new era of brain-nanomachine interfaces that can link a person’s mental state to “bioactive payloads” and future techniques that build upon this prototype could be helpful in the treatment of schizophrenia, depression or other mental disorders – because the drugs in question only activate when a patient’s brain waves show signs of abnormality. Hacking a cockroach’s – or eventually a humans – bodily functions with just your thoughts is a staggering concept to get your head around in the first place but the scientists developed their technology with another goal in mind – to solve a thorny problem in drug delivery.
  13. I'd like to kick this thread off with a cool thingiverse front loader.
  14. Big thanks Daniel. OpenRC is the best thing that has come along since sliced cheese Any plans to make an OpenRC backhoe, loader, dozer, skid steer? I'm sure folks would love to see an OpenRC semi truck comparable to the tamiya king hauler. I'm hoping you'll say yes.