Merry X mas everyone. I have managed to avoid my daughter painting everyone's finger nails now so can go back downstairs now. ><by aka47 - Controllers
Interesting methods A friend of mine built a number of reflow ovens to order they were actually quite simple. (In the very early days of SMT components) He used Long Wave IR to heat the boards up and they were passed under the heating elements on a chain/mesh conveyor. Temperature sensing was done by a sensor just of to one side but still under the elements that overlapped the conveyor (big naby aka47 - Mechanics
As it is a touch new I didn't really expect it to be that cheep (Shame realy), but for what you are getting compared to other technologies it is comparatively cheep. Lowest cost source is probably going to be straight out of a cheep mouse in the short term. (The cost will have to be competitive with other optical solutions and these retail at the same or less than you suggest the chip on it's owby aka47 - Mechanics
Guys Sorry to sugest something a little simpler but I just found this whilst having a rummage through Cypress Semi's web site They do a nearly all in one laser navigation chip aimed at the mouse market (Read cheep) umm it doesnt need a mouse mat etc either. It does do X Y but I guess we could use it for one axis anyway and if you wanted use the spare axis to check up on backlash and end floatby aka47 - Mechanics
Whilst the torque to supply arrangement is not at all linear for the purpose of explain the principles, we will consider it so. Assume that running a motor wound for 24v but run at 12v will give you half the spec at least (More likely less) this means that, yes you could probably run it at 12v you would draw less current and develop less torque. ie less speed and power. Virtual all motors can bby aka47 - Mechanics
This switched reluctance thingy sounds remarkably like a bunch of literature I read some time ago about running induction motors as generators. They sound to be about the same and have the same non-self-start issues. the way they got around this was to flash some of the Stator Coils with a car battery just enough to give the rotor a very slight residual magnetic field. It was enough to bootstrby aka47 - Plastic Extruder Working Group
Viktor I think we are agreeing. Where each move is single step the start line is synchronous on a step by step basis and therefore in reality equivalent to a clock. You don't therefore need all axis controllers resident on one board, although you can make it so if you like. You can also have as many axis controllers as you want. Try 5 for example and make articulated arm. Where you are plannby aka47 - Controllers
Hurro guys I had missed this thread. At the risk of opening some old issues. To synchronise moves on a per axis controler board it is enough to have a wired "or" line between all the boards (works in a ring too, of course). Basicaly any board in the process of a move asserts the wired or to true. Any or all of the other boards can also assert the line to true simultaneously. When a board haby aka47 - Controllers
Ok guys AKA A worked Servomotor example Under the Motors area is the place for contributing to a worked Servo Motor one per Axis Design. As Linus's Biography suggested.......Just for fun..... (Is standing on the shoulders of giants fun ? Maybe it's an extreme sport.) aka47by aka47 - Mechanics
Funnily enough After posting the above and sending fed up emails to MFA/COMO I finally got a verbal reply (Nothing in writing though) That the minimum order for the 12v (instead of 24v) motor in question with the extended shaft is 2000 at a unit cost ofby aka47 - Mechanics
For design process, I think more folk will use it if they have participated in the design and implementation. What's the form with the Wiki for this project (bunch of projects ?) I think the design work etc would best be done as Wiki Documentation alongside forum discussion. This gives more folk the ability to participate and winds up with a formalized set of doc/s that describe the design suchby aka47 - Mechanics
Already part way there zack, I have put up a worked servo motor example just for fun on one of the other forum threads. What I am working on at the moment is a universal 1 per axis servo motor design. The H-bridge power stage will be built from discreet N type MOSFETs and is likely to be driven by a pair of high/low side Gate drivers. (LM5100A/B/C, IR2011, HIP2100 or some such) The gate driveby aka47 - Mechanics
An update re MFA/COMO The motor/gearbox I used in the illustrated example is 12v unfortunately they only do the same but in 24v if you want to mount an encoder on the rear end of the armature. Despite their website suggesting that they could do specials for larger orders they seem to be reluctant to give me any figures at all for supplying the 24v extended shaft version in 12v. So much so (Incby aka47 - Mechanics
Hurro Zach I agree, there are effectively three threads in one, one discussing the where we are now, one discussing technology comparatively and a third to discuss what next. I struggle to agree that any technology is "Superior" to any other merely more/less optimal a solution to a given problem. On effort something to consider. For a software oriented individual with the tools to hand moreby aka47 - Mechanics
Viktor In the interest of economy I am with you on using what is to hand "The everyone else" approach. Unfortunately I don't have such stock to hand Like yourself I have a history of looking inside printers etc and seeing how they worked (I did IT Component level repairs and Field Service for a while, as well working for an instrument manufacturer as a design technician) I guess this has contby aka47 - Mechanics
Sean The dash dot idea is a good one purely for position sensing by a controller that is compos mentis. Using the minimum of Hardware. It does rely rather heavily on the controller monitoring the duration of interruption versus travel distance instructed. (Tweaks to software) If the controller isn't with it (accumulated error or crashed software) you may smash the assembly into the end stop anby aka47 - Mechanics
Hehehehehe This sounds like immense fun. Whilst doing some work for British Rail Research as was, in Derby A guy who used to work for Rolls Royce Research in Derby testing turbine design/construction showed me pictures and bits of turbines that came unstuck at high rotational velocities. Many of the bits were embedded in the thick concrete wall of the test pit that they used as a safety featurby aka47 - Plastic Extruder Working Group
Bob I think you are (probably quite understandably) confusing what I mean by magnetic material or may be I confused what I meant by magnetic material. I am referring here to using material that is compatible with a magnetic circuit ie ferrous material. Not actually directly constructing a magnet as such. But be sure that a magnetic circuit will at some time or other become energized with flux.by aka47 - Plastic Extruder Working Group
Brian The usual fix to this is to use a cutter that is in effect mounted on a very short swivel and therefore doesn't need motorization to reorient the cutting edge to the direction of travel. A bit like the castor's that are put on furniture and trolleys. Take a quick look at Drag Knives and Vinyl Cutters/Cutting. I guess the shape/length of the cutter etc also has quite a bearing on how wellby aka47 - Mechanics
Most interesting. All seem to exploit the same principle. that of an optical linear reference bounced of an object and its apparent displacment by a 3d object picked up by a camera/array placed at an angle to whatever generates the linear reference. (Linear only in that if projected onto a flat plane it makes a straight line) Main differences being, linear shadow v linear strip of light (cohereby aka47 - Plastic Extruder Working Group
Bob I don't think that I for one doubt anyone else's seriousness or sincerity. I wouldn't be spending my time helping other folk if I did. (Better things to do) The observations re eddy current and induction furnaces remain. The greater the power you are considering in your experiments the greater the losses and the more likely that things will get hot where you don't want them to in a way youby aka47 - Plastic Extruder Working Group
Hmm I can see where you are going with this. Re the J shaped tube I still think that a tube with a flared trumpet shaped mouth (Shaped exactly like the inner curve of the hooked part of the J) would give you the same degree of control without the need for extra motoring or even castoring (same effect but unmotorized and therefore simpler). The electro gripper as a way of starting off though iby aka47 - Plastic Extruder Working Group
OK Take a quick rummage through here. The guys are currently going at this one with gusto. aka47by aka47 - Mechanics
Not being a mechanic I struggle with some of the understanding sometimes. Bearings can be a very confusing subject for what is really quite a simple subject (or are they ??) I found this explanation of bearing types, properties and what all those type numbers mean. For detailed specs you really need to look at each manufacturers data but this may help you make sense of the mechanical bearingby aka47 - Mechanics
I see This is similar to aome technology A company I worked with used to measure the clearence around rail tracks from an instrument car. (I actually saw the unit again just recently at the train station in Doncaster so I guess it is still on the go) they used a very bright light in the center of the instrument car directed with a pair of flanges around the skin of the car and had CCTV gear moby aka47 - Plastic Extruder Working Group
How about an Inkjet pen I have seen/worked machinery that had these (very expensive) It's sort of an ink jet head that relys on the parts moving under it (except that we move the ink jet head, it's all relative motion after all). I worked with Ferodo for a time making brake linings and the machinery used these to write the part numbers on the edges of the linings as they went down a conveyor.by aka47 - Mechanics
Just thought Cutting laminations out of thicker material (taking into account previous comments re induction furnace) is probably going to be more cost effective/easier with a plasma torch. aka47by aka47 - Plastic Extruder Working Group
I think you will need a drag knife too or a spray tool to cut/deposit some form of insulation/adhesive on the laminations. Laminations that are electrically connected have limited value they loose a lot of energy through promoting eddy currents. Make a circuit in the right direction (Flemmings right hand rule) and you have an induction furnace....... aka47by aka47 - Plastic Extruder Working Group
Bob I followed all the first bits but am struggling with picturing the J shaped tube and why it is necessary. This is not to say that it' isn't necessary, clearly you feel that it is. Why would an unmotorized trumpet mouthed tube/tip not work.... (Sort of J shaped all the way around). Coil winding is something I also have a need for being interested in alternators and windmill's not to mentioby aka47 - Plastic Extruder Working Group
On the subject of lost foam. Add lost wax. I am not that familiar with lost foam (can someone explain) but am with lost wax. You can even get lost wax blanks for carving cheaply here in the UK from Design Technology (making things at school) materials suppliers. So lost wax could be achieved in one of two ways. Carve out from a block with a router head (Dremmel etc or some such) or extrude cby aka47 - Mechanics