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Robots, children's blocks, wooden clocks, its all good! Here's my idea and here's the [[page]] on RepRap's wiki where we can log in and click "edit".
Re: Extendable Z-probe with Shape Memory Alloy actuator - 1 year ago
QuoteVDX ... you could add a jet of cold air to reduce the recovery times The cold air jet could be switched on and off by a valve with an SMA actuator. The slow recovery time of the valve could be improved by a jet of cold air which.......... Must stop adding complexity. The latest development removes the push-rod entirely and replaces it with a swing-out lever reduces the weight by about 1by leadinglights - Tech-Talk
Re: Extendable Z-probe with Shape Memory Alloy actuator - 1 year ago
From an admittedly short search for info on Magnetic Shape Memory Alloys like Ni2MnGa, it looks like the magnetic driver will have to be too big to be usable - I will retire that for some future use. A quick test with a bistable Nitinol actuator powered with short pulses of high current to switch states looks promising. It looks like I can get everything I need as long as I can allow > 2 secoby leadinglights - Tech-Talk
Re: Extendable Z-probe with Shape Memory Alloy actuator - 1 year ago
Thanks Viktor, I will look into NiMnGa alloys which I haven't come across before. Hopefully I will be able to find a less stratospheric price - for example, Nitinol can be had from Sigma Aldrich for £320 for 1 meter or through Amazon for £1.39 per meter from Formgedächtnistechnik. The "counteracting" SMAs method looks good at the moment, possibly having PCBs with the SMA actuators and driverby leadinglights - Tech-Talk
Extendable Z-probe with Shape Memory Alloy actuator - 1 year ago
This is a Z-probe touch sensor with an SMA (Shape Memory Alloy) actuator to extend the probe tip. In order to see the fine detail of a contact event, I have used a piezo disk as I am familiar with both the vices and virtues of these devices. I have put this on this forum in the hope that it may be of use to others; but also in the hope of some useful input from others. A proof of concept deviceby leadinglights - Tech-Talk
Re: Heatsink pastes for hotends - 2 years ago
Having just switched off my test rig, here is the promised report on how the heatsink compound held up: After 1400 hours at 240°C with a thermal load set to dissipate about 20 watts there was no observed change in the resistance of the 18Ω resistor. There was some discoloration as seen in the photo below but no cracking or crazing of the insulation was found. The resistor was a Vishay Sferniceby leadinglights - General
Re: Air gauging for filament size - 2 years ago
A quick report on this project. It is not going too fast although I have managed to put together a loudspeaker air-mover which seems to move enough air at frequencies from 20Hz to 60Hz to get a response on a MEMS pressure sensor. Examination of the changes in waveform of the response is making a return to the constant flow method look attractive. Recently I have become aware that Murata has prby leadinglights - Tech-Talk
Re: A Very Different Extruder - 2 years ago
I can't see any problems with your test cube but 11,100 steps per mm?? I wonder if this is an opportunity for all the redundant 15 and 7.5 degree steppers in junk boxes everywhere? I have always found "face palm" moments to be rewarding. Mikeby leadinglights - Tech-Talk
Re: Delta printer ball joints, let's talk! - 2 years ago
@rq3, With an attachment force of 1.25kg to 1.8kg I don't think that you will be having any problems with your magnetic joints failing to remain properly seated. Jerk is likely to be the main area of problems as normal acceleration has only the mass of the effector to contend with and six magnets to hold everything together. When I used steel cups in my design I noticed that there were many appaby leadinglights - Delta Machines
Re: Delta printer ball joints, let's talk! - 2 years ago
From previous experience, I was already happy that using a steel cup on a magnetic joint is not a good choice, but I didn't know the scale of the problem. A good way to put this into some sort of scale is to make a model and take measurements of the force required to move the ball from its seated position in the cup. The rig consists of a steel disk (18mm dia x 3mm thick) to simulate a ball butby leadinglights - Delta Machines
Re: Delta Printer building - 2 years ago
I think what you may want is this I think there may be some other similar programs as well but this is the one I have used. Each of them look for errors in many parameters such as Delta arm length, Delta radius etc... Mikeby leadinglights - Delta Machines
Re: Delta printer ball joints, let's talk! - 2 years ago
@jcs, I had not thought about a spherical magnet but have some in my box of oddities so did some very cursory checks and I lean towards rq3's opinion that good alignment with a cylindrical magnet is problematic. I did however find that you can get an excellent magnetic attraction for very little mass by using two cylindrical magnets with a magnetic ball between them - the total mass of this jointby leadinglights - Delta Machines
Re: Delta printer ball joints, let's talk! - 2 years ago
Firstly I must apologize if my postings in this thread were somewhat ambiguous. My experience and tests indicate that iron cups and even the countersunk in countersunk magnets are a bad thing and not suitable for magnetic joints in delta printers. Quoterq3 .............................. Also, a disc magnet with a hole in it has a hole (a weak spot) in the center of its field. By placing a solidby leadinglights - Delta Machines
Re: Delta printer ball joints, let's talk! - 2 years ago
There is nothing inherently wrong with metal to metal for rubbing parts although I am not sure the plating on magnets is a good candidate. I prefer to use a plastic cup - Delrin in my printers I did a quick test with a countersunk magnet and a ball to check if the results were the same as with my iron cup test. On first results it doesn't look like having a ball nestled in the cup of the magnet iby leadinglights - Delta Machines
Re: Delta printer ball joints, let's talk! - 2 years ago
@Gaou, When you said that you thought that the magnets were too strong It sparked a memory. Unless the geometry is severely out of whack there should not be a condition where the effector is tilted away from where it was set - and yet that was exactly what I have seen when I first designed my own magnetic rod ends. It turned out that I had made a bad design choice: I made iron cups out of high peby leadinglights - Delta Machines
Re: A Very Different Extruder - 2 years ago
Just a passing thought: Is it possible that this would work with only two wheels? At first blush, this sounds silly as the filament would pop out sideways as very under-constrained. However, the sideways force may possibly be easily constrained with guides if they were slippy enough or maybe with guide bearings just beyond the ends of the drive bearings. The question is, how big should the wheelsby leadinglights - Tech-Talk
Re: Is this resistor suitable as a heater for the hot-end? - 2 years ago
Using some component or product for a purpose for which it was not designed does have several problems. You may find that a resistor might be better heater than a purpose made cartridge; but that does not mean that similar resistors are as good. This is a problem with other parts as well and many examples are found in the RepRap printers:- An M8 threaded rod made for the building industry will tby leadinglights - Reprappers
Re: A Very Different Extruder - 2 years ago
I looked at the FuseLAB extruder on - explanation of the mechanism of working from about 4:30. It is a bit chunky and complicated - rq3s extruder is smaller and simpler and more likely to be the basis of a RepRapable extruder. btw, MKSA - your new mildly humorous sarcasm is better than your normal unrelentingly negative sarcasm - there is hope for you yet but please dump the stupid sigline abouby leadinglights - Tech-Talk
Re: A Very Different Extruder - 2 years ago
Thank you for all of the detail. My only remaining question is with regard to the "nest" between the three bearings: With a bearing diameter of 10mm there is only enough space for a filament larger than 1.55 mm in diameter - barely enough to get a grip on 1.75mm filament. With any clearance between the bearings, and in particular, if there is a diamond coating, the nest may become too big to getby leadinglights - Tech-Talk
Re: Is this resistor suitable as a heater for the hot-end? - 2 years ago
The most likely area where it will have become intermittent is where the nichrome wire is spot welded onto the end caps. On older vitreous resistors the end cap is a nickel steel alloy (on Vishay-Sfernice resistors) and this welds cleanly with the nichrome - the temperature can be cycled repeatedly without the weld failing. On the newer silicone resistors, the end caps are carbon steel which is fby leadinglights - Reprappers
Re: A Very Different Extruder - 2 years ago
I am most intrigued, can you give a few more details? How much of an angle are the bearings at? - This is only hinted at in the photo. What size of bearings? How is the pressure of the bearings on the filament maintained? What is the roughed finish on the gripping surface of the bearings? Mikeby leadinglights - Tech-Talk
Re: MechaBits KraftWerk'r - 2 years ago
Next year??? First I get told that I will have to wait until next year for the next series of "Line of Duty" and now I have to wait until next year to know how you configure the SKR Mikeby leadinglights - Extruded Aluminum Frames
Re: Air gauging for filament size - 2 years ago
O.K., the first results are in. The first thing of note is that the errors are somewhat more on filament than they were on the metal test pieces. Having said that, an error of 25 microns is just about one thou in Olde English (or one mil in Olde American) It is also about 1.4% of the diameter or 2.8% of the area. The Woodfill filament gave readings on the air gauge consistently lower than thby leadinglights - Tech-Talk
Re: Xmax stuck triggered, even when uplugged - 2 years ago
Is it possible that the software has been changed? If the pull-up for the Xmax is enabled and it is set to be triggered when high then it would always show as triggered - even with the limit switch is unplugged. Mikeby leadinglights - Tech-Talk
Re: Air gauging for filament size - 2 years ago
The first iteration of this back in 2016 was 3D printed (picture below) but I used 20mm earphone speakers both as a driver and sensor. As it needed to work with these small speakers which had very limited cone travel, the frequency response of the speakers and the rest of the system made for very peculiar and unpredictable responses. Using much bigger speakers with a long travel on the cone allowby leadinglights - Tech-Talk
Re: Air gauging for filament size - 2 years ago
Hi rq3, I haven't settled on a driver yet, but I am orbiting around using a speaker to move the air, specifically the Visaton FRS 5 X Loudspeakers have a much longer life than any pump and the output is less affected by things like temperature, humidity and dust. It is true that MEMS barometers are cheaper than gauge or differential MEMS devices and quite often offer greater accuracy. OTOH, asby leadinglights - Tech-Talk
Re: Filament measuring thingy - 2 years ago
Hi Joshua, I have put up some preliminary results in the Tech-Talk subforum at . I thought that that would be a better place than the general forum what could be lengthy threads. Mikeby leadinglights - General
Air gauging for filament size - 2 years ago
This is a continuation of an entry in the General subforum I thought that it may get more interest in Tech-Talk. In brief, this is a device for measure the rate of plastic flow in a 3D printer that measures the cross-sectional area of the filament by measuring the restriction to the flow of air through an orifice through which the filament passes. This technology is known as air gauging and isby leadinglights - Tech-Talk
Re: Filament measuring thingy - 2 years ago
Two weeks ago I had an email inviting me to join a discussion about an open-source filament diameter sensor I commented in this discussion to point to this thread and other methods including my own air restriction method and the capacitative sensor proposed by frankvdh I found in the discussion that the air restriction is well known and potentially accurate and is called air gauging. Having neby leadinglights - General
Re: Looking for new contol boards and firmware - 2 years ago
@deckingman I will await your return to the forum and of course to YouTube fully invigorated with lots of new and interesting ideas and designs. btw, you are but a spring chicken. I celebrated my 75th a week ago. I would normally keep my antiquity top secret to avoid inducing culture shock in the under 30s, but I seriously doubt that there are many who read this forum. Mikeby leadinglights - General
Re: Is this resistor suitable as a heater for the hot-end? - 2 years ago
I was an early adopter of heater cartridges and abandoned them when the majority of those I purchased turned out to be faulty. I would think that they have improved considerably since the ones that I purchased, but that is no reason to change from resistors to cartridges as long as resistors remain reliable - which they have. I do have some of the original cartridges that were within spec. Thoseby leadinglights - Reprappers