Permission to publish and distribute this document was given by Nophead. The original text and images have been extracted and converted to pdf by means of a script.
This may have resulted in formatting errors or incorrectly transferred text. Please note that dead links may result in missing images. Comments have not been extracted, these can be found on the original blog site, a link to each blog Fiat Marea Weekend 185 1996-2002 Banner Running Bull Agm 60Ah Battery Replace is given at the top of Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery post in this document.
Please report any errata to contact garyhodgson. I have been collecting motors and other "useful" junk for years and have at last found something interesting to do with. My hobby, starting as a child, used to be electronics but it is Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery hard to find something to make that you can't buy cheaper and better.
Consequently I haven't built anything at home recently. My skills lie in electronics and software and I can get by in woodwork and metalwork which I learnt from my father who was a Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery by trade.
This project involves all these disciplines plus material science and chemistry which I know virtually nothing about but am interested to learn. In short, making machines that make other machines is the perfect hobby for me.
Hopefully my experiences along the way may be interesting to others so I decided to start this blog. A bootstrap machine has to be made by hand. This has come Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery be known as a RepStrap machine in the RepRap community. Lots of Seat Toledo Mk2 Mk3 Mk4 1998-2016 Vetech Battery 70Ah Electrical Replace Part are trying different approaches using whatever materials are easy to come by locally.
Wood, Lego, Meccano, copper pipe and drawer slides have all been used by different RepStrappers. The machine needs three axes of motion and an extruder head to extrude molten plastic filament. Most Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery machines use threaded rod as a means of creating accurate linear motion from a stepper motor for the axes.
This was Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery approach I was planning to take when I started looking at this in mid January. I had a look at how professional CNC machines are put together and saw that the prices are a lot more than I wanted to pay but the accuracy and speed was a lot better than I could hope to achieve with drawer slides.
I had a quick look around to see if I could get anything second hand or from the surplus market. This gave me the idea that I could make a very accurate machine that is also stiff enough to do milling.
It also came complete with a pair of MDM7 stepper motor drivers. These are bipolar, constant current, micro-stepping with anti-resonant circuitry and opto isolated inputs, i. Perhaps I should explain each of these terms: If this is done with a single coil per electromagnet then the electronics must be able to drive a positive or negative current into each coil. This is bipolar drive and Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery four transistors per coil, i.
Alternatively the coils can be centre tapped which effectively creates Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery coils per electromagnet wound in opposite directions. One of these can be energised at a time to produce opposite magnetic fields. This only requires one transistor per half coil, i. The advantage of unipolar is that the electronics are cheaper but as only half of the windings are energised at one time the amount of torque available from a given size of motor is.
The field produced by an electromagnet and hence the torque of the motor is proportional to the number of turns times the current. The maximum current that can be applied is limited by the maximum allowable temperature rise.
The heat generated Lamborghini Lm-002 1985-1992 Vetech Battery 70Ah Electrical System Replace Part the windings is proportional to current squared times resistance. This means that if a unipolar motor is operated in bipolar mode then the maximum current is root two times less because the resistance of the full winding is double that of the half windings.
However, the number of turns is doubled so the torque is root two greater. Constant current versus constant voltage Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery simplest way to drive a stepper is to apply a constant voltage to the coils. The problem with this is that when a voltage is applied to a coil the current builds up gradually at a rate proportional to the voltage divided by the inductance until it reaches the steady state defined by the voltage divided by the resistance.
This causes torque to fall off with speed because at higher step rates the Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery does not get time to reach its full value before the Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery step.
A better driver system is to apply a much higher voltage to the coil to get the current to rise quickly and then turn it off when it reaches the correct value. The current then starts to fall at which point the voltage is applied. In this case it increases the Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery of steps from to per rev.
As the screw threads have half an inch travel per rev this gives me a step size of a th of an inch or just over 6 micrometers. The target for RepRap V1. The only downside is that the maximum travel is only mm in each direction compared to Darwin's mm. Another advantage of micro-stepping is that it produces smoother Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery at low speeds. Anti-resonance Because the force applied by the motor increases as it is Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery from its resting position it behaves like a spring.
This together with the mass of the rotor and the load forms a resonant. This is a major problem with high speed operation of stepper motors. An anti-resonant drive monitors the drive waveforms to detect when resonance starts to occur Lancia Phedra 179 2008-2010 Bosch S3 Battery 56Ah Electrical System Replace Part adjusts the drive current to dampen it.
This allows the motor to be stepped through its resonant band to achieve higher speeds. Opto isolated inputs The step Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery direction inputs are electrically isolated from the drive electronics by opto couplers. This avoids heavy motor currents sharing the same ground path as the logic signals, which can cause signal corruption.
The XY stage also includes hall effect limit switches and step shaft encoders. A great find, the challenge now is to build a Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery that does it justice. Here it is being put through its paces with a signal generator on one axis. With a bit of ramp up and ramp down I think it would go well above 10kHz. Also I have the full windings connected for maximum torque. The motors are centre tapped so I have the option of using half the winding.
Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery gives root two less torque but one quarter Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery the inductance, so should be better for higher speeds if needed. Not quite such a bargain as the Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery table as it does not include a stepper motor, limit switches or electronics but I am pleased with it all the.
It is very solid so I should be able to mount any type of head I want on it. It has a mount for a Nema frame motor.
I have a few of these lying around but unfortunately the shaft exits from the wrong end so I will have to mount one on pillars. Each rev of the leadscrew moves the carriage 20 mm so I will get a resolution of 0. It doesn't need to move very fast so I will try to get away with a simple constant voltage unipolar drive circuit.
I decided to make a small but highly accurate milling machine. With this, Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery the small watchmaker's lathe I inherited from my dad, I should be able to make Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery plastic filament extruder.
I should also be able to mill and drill the Darwin PCBs. Once I make the Darwin I will be synchronised with the RepRap project and thus able to make the successive generations, whatever they may be, because the RepRap idea is Fiat Bravo Mk1 1995-2001 Banner Power Bull 62Ah Battery Electrical Replace Part each new generation can be made by the previous one.
That was my original aim Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery my axes should out perform the Darwin axes in all respects except build volume.
Darwin aims to achieve 0. I expect to get 0.
That means rather than just using my machine as a RepStrap I will continue to use it for anything that doesn't need the larger build area. I then got the idea that I would be using many different heads on the same Cartesian engine, hence the name HydraRaptor. Initially these will Abarth 500 312 2008-2016 Banner Starting Bull 44Ah Battery Electrical Part manually exchanged but I have a plan to mount the heads, spoke like, on a rotating wheel fastened to the z-axis.
However, I decided Fqst prototype it in MDF first because it is much quicker and cheaper to work in wood. As Faast Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery out it was just as well I did! MDF is my favourite wood because it comes perfectly Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery, with straight edges and right Fiat Doblo Cargo 223 2001-2010 Banner Power Bull 50Ah Battery Replacement corners.
No grain or knots to worry about either, the only problem is the Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery which gets everywhere Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery is allegedly carcinogenic. I have a foldaway workbench in the garage made from an old front 740 with a sheet of MDF over it.
The door's original hinges are used to let it swing up from the wall and it has hinged legs that drop Fqst as I pull it. This allows us to keep a car in the garage, something very few Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery seem to do these days. The bench has woodwork and metalwork vices and three interchangeable Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery Titaniumm I can mount my bench sander, drill press and band saw.
These are stored on a shelf above the height of the car. One day my wife and I heard a crash which sounded like a car crash in the front garden. We ran to the window but nothing was happening outside. We had just got a new TV with surround sound so we thought it must have been part of the film we were watching. The next morning when my wife went into the garage she found the shelf and all my tools on top of her car! It did so much damage she still hasn't forgiven me ten years on. The first thing I did Dellivery start my build was to cut a base board mm square from a sheet of 18 mm MDF.
I placed this on the bench while I adjusted the band saw for the next cut. Somehow I managed to knock the sheet off and it landed on my big toe. The pain was the worst I have ever experienced. It left a pair of Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery mm tram lines across my leather shoe as you can just make out below: The toe recovered but the shoe didn't.
I can see now why Fst dad always wore steel Baftery capped "totector" boots when he was working. Inspired by Caf shape of my bandsaw I decided to make Titanium 334 / 250 Sealed Car Battery 12V 740A - Fast & Free Delivery G shaped construction.