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Here's what I made, here's a photo, and here's a link to the [[page]] on RepRaps wiki!
Re: Over Constrained Linear Systems - 12 years ago
Your description of degrees of freedom is a sound one. It was one that was incorporated in the original reprap design. See below. Reprap axis design video This is a sound theory, but in the real world was not found to be the whole story as suggested by Chris above. The original designers thought that the mechanism would not be accurate enough for parallel rails, but this has been found to be unby martinprice2004 - Mechanics
Re: Vertex-foot cast in aluminium - 12 years ago
"Raised bosses" When you need a flat surface to bolt to, you produce casting similar to as show above. You then machine just the tops of the bosses only and you get a very accurate and square surface to run the nuts up to. It saves you machining the whole surface. Spot facing is another alternative. By doing things this way, you may be able to machine them on your CNC as the metal removed isby martinprice2004 - Look what I made!
Re: Vertex-foot cast in aluminium - 12 years ago
Looks great. Perhaps you could revise the part so its easier to cast. 1) Reduce the thickness in certain areas. Aluminium casts better when the part has uniform wall sections. 2) Have raised bosses around the holes. This way you can flash machine them off quickly to make a very accurate part. 3) Re engineer it so it uses less material. You could drill the wooden master and rework it. 4) Increaseby martinprice2004 - Look what I made!
Re: Fiberglass thread extruder - 12 years ago
I think chopped mat would make things much easier as its used regularly in plastic injection to improve mechanical strength. 30% chopped mat in nylon is used regularly for automotive engine parts. A cheap filler material in plastic would also help to reduce the cost which is a limiting factor in printing large objects. Perhaps printing plastic, then powder in altenative layers may be an option.by martinprice2004 - Wire and Thread Embedded Extrusion
Re: Some thoughts on a cheap, fast and accurate SCARA reprap - 12 years ago
Heres my attempt at a SCARA robot. There is a video half way down of it moving. Helium Frog SCARA Robot The Z axis lead screw is very slow, so I am currently developing a belt driven Z axis. I think this will then make an effective pick and place robot. Resolution of my robot is less than a Reprap, but with 400 step / rev motors and the gear ratio you see on my robot, the resolution does approby martinprice2004 - Developers
Re: arm robot may have only 2 motors - 12 years ago
A cartesian robot could be capable of 3D movement with two motors. Old typewriters had a carruage return mechanism that could be used on a cartesian robot. XY motors would work as normal, but when you wanted to index in Z you could home to one end and hit a trigger to raise the Z axis (Other end could lower the axis) What must be borne in mind is that motors are relatively cheap nowadays and thby martinprice2004 - Polar Machines, SCARA, Robot Arms
Re: Quad-Copter - 12 years ago
Quadcopters dont fly well with one motor disabled, they will flip and be unable to control direction and torque. The main reason that quadcopters are most popular is that they are the simplest to construct. Helecopters, bicopters and tricopters need a fan tilt mechanism to control torque and direction. This means there is usually an extra servo or two below the motor so the fans can be tilted. Tby martinprice2004 - Let's design something! (I've got an idea ...)
Re: Rostock delta robot now moving at 400mm/s - 12 years ago
Looks a really neat design. I was wondering how good a belt driven delta would be and it appears that the movement is very good and quick unlike my lead screw driven one. The universal joint implementation is also really neat. Has it shown any signs of wear yet? I also like the labyrinth method for attaching the belt to the moving carriages. I was wondering about your choice of firmware. Usingby martinprice2004 - Delta Machines
Re: Quad-Copter - 12 years ago
Here are two links to a design that is already complete. Its printed on an ultimaker Quadcopter on thingiverse Quadcopter video Probably the most appealing one to the reprap community would be the "arducopter" (just google it for several links). As its arduino based, a lot of the community here would be familiar with the electronics. There is also a good link here to a micro quadcopter whichby martinprice2004 - Let's design something! (I've got an idea ...)
Re: Z axis M8 nuts riding up / sometimes no movement on Z axis - 12 years ago
Yes brass nuts on steel is a good idea. I have just ordered some for my machine. Traditionally phosphor bronze nuts were used on lathes which is better. You can still get them if you shop around. They were generally replaced by brass due to the rising cost of bronze.by martinprice2004 - General
Re: Extruder Heater: Reaches Temp, then termistor not readable - 12 years ago
There is an over temperature protection in the firmware. It shuts down the hot end if it goes over a set temperature. It can do this mid print which is a pain. My printer worked fine for weeks , then I had this issue. Its probably due to interference in the cabling when I resited my printer. There are reading spikes from the thermistor, one of which triggers the over temperature protection. Checby martinprice2004 - RAMPS Electronics
Re: ABS on Glass with abs juice - 12 years ago
Have you tried letting the glass cool a little, then putting it in the freezer for about 10 minutes. I print on aluminium / kapton and freezing the plate works quite well you can bang the parts off with a quick tap on the edge of a table. It should work better on glass than aluminium.by martinprice2004 - Reprappers
Re: Purchasing in the UK - 12 years ago
GT2 is not easily avaiable in the UK. You would have to phone up suppliers and ask for them. T5 belts are easily available. www.beltingonline.com are very good and deliver quickly. They also do T2.5 if you want to go a little smaller pitch. The main problem with small pitch is that the gears would be a bitch to print on your reprap when you want a spare. T5 pulleys can be printed with a standarby martinprice2004 - Reprappers
Re: How to find stepper drivers microstep setting? - 12 years ago
Yes stepsticks only do 1/8 microstepping. I was scratching my head the other day trying to get 1/16 out of some and failing! The MS3 jumper does nothing on them. You will soon know if you have these as everything you print will come out twice the size.by martinprice2004 - General
Re: Granule Extruder for large custom 3D printer - 12 years ago
Looks a neat design, there doesn't appear to be any flaws in your thinking from what I can see. Have you done any trial feeding granules down a tube to replenish the hopper? I know this is quite difficult to do so this may be your main problem. Powder and granules are sometimes transported using a fluid bed (Air pumped into the granules so they behave like a fluid) so this might be an option.by martinprice2004 - General
Re: Helium Frog HF06 "SCARA" Robot - 12 years ago
Just uploaded a video of the robot on YouTube SCARA Robot Video Link I havent implemented any acceleration yet, but it is capable of moving at 100mm/sec in X and Y without any problems. Z axis is very poor at only 5mm/sec. I might try to implement a belt driven Z axis or try a larger motor.by martinprice2004 - Robots!
Re: Tom's HexTruder - 12 years ago
You mean something like this? Cam Extruderby martinprice2004 - Reprappers
Re: Solid Model files for Prusa Mendel - 12 years ago
Lets face facts. You wouldn't use OpenSCAD if a proper CAD system was on the market for an affordable price. I haven't yet downloaded a .stl model from thingiverse that wasn't awful and had surface errors. They are all incorrectly scaled (usually 25.4 x bigger due to imperial / metric conflicts). The .stl file is also massive when imported to another CAD system which can cause issues. As a furthby martinprice2004 - General
Interesting Video - 12 years ago
I found this video of a robotic bee which I thought might be of interest (no pun intended). robotic bee video Some things to note which might be of relevance to the reprap community. 1) The use of Kapton tape. It appears that they use it as a hinge (living hinge) when placed between solid layers. 2) A support structure which helps with bending and assembly and is then removed. 3) The use of aby martinprice2004 - Robots!
Re: Problems with 16x microstepping - 12 years ago
Ah yes I think that is the issue. They use A4984 chips which only support 8th step. Perhaps they differ from the A4983. This may also explain why my electronics run cold. I think they handle higher current. I will have to compare the specifications.by martinprice2004 - RAMPS Electronics
Problems with 16x microstepping - 12 years ago
I am having a problem with 16x microstepping on a RAMPS 1.4 board. All jumpers are set to 16x but the motors seem to only be capable of 8x microstepping. I have checked the firmware and done a sanity check by writing a little program to pulse the motor for 1 rev. It takes only 1600 (200x8) to complete a revolution. Motors are Nema 17 SY42STH47-1684B (200 steps per rev) running Pololu Drivers.by martinprice2004 - RAMPS Electronics
Re: My stab. - 12 years ago
My delta robot has some simple software to run it here. The software link is on the blog page. My robot was a parallel type with linear bearings, but to use it for your machine you would just need to modify the 3 equations in the delta routine. These equations should be available on the net.by martinprice2004 - Delta Machines
Re: Suitable glues for heatsinks? - 12 years ago
I just use regular quick setting epoxy. Just a very thin layer so it doesnt affect the thermal conduction too much.by martinprice2004 - General
Re: Removing finished prints - 12 years ago
Thinking ouside the box for a moment, most parts could be remodelled with a little chamfer around the base, say 1mm x 45Deg. Visually you probably wouldn't notice the change, but it would give you a little gap to get a spatula under the corner to lever the part off.by martinprice2004 - Printing
Re: hybrid printing/milling - 12 years ago
The Hydra MMM machine was an attempt to do this. Follow the link below and through to the blog using the link on the right of the page. Hydra MMMby martinprice2004 - General
Re: Stepper doesn't turn - 12 years ago
@ Dorphaus I have looked at the video. Two things spring to mind. 1) Incorrectly adjusted current (You have probably already tried this) 2) One motor coil wiring is inverted and they are fighting against each other. When you checked the wiring, did you just check the connections only or check which way around the coils are. Disconnect pin 1 and 2 and check with a multimeter. You should get conby martinprice2004 - Stepper Motors, Servo Motors, DC Motors
Re: Delta rep rap kit - 12 years ago
I think this would be popular if you achieve what you state, but it will be very difficult to get a delta to this sort of accuracy. Delta robots are notorious for tool head shake due to the long arms in the mechanism, so your actual machine accuracy (not resolution) is likely to be very low. Just go to youtube and type delta robot, then watch the tool heads of the robots. They wobble and shake wby martinprice2004 - Delta Machines
Re: Removing finished prints - 12 years ago
I clean my kapton tape with acetone regularly, which makes the parts very difficult to remove. For ABS on a 6mm aluminium plate with kapton, I have found that about 10 minutes in the bottom of the freezer helps a lot. The plate comes out ice cold and a sharp smack on the edge of the table gets them off. For very large parts I sometimes have to resort to a knife or ruler under the corner, but thisby martinprice2004 - Printing
Re: Helium Frog HF06 "SCARA" Robot - 12 years ago
Thanks for the links Viktor The parallel SCARA looks a better concept as the motors are mounted further back and it would be more rigid with two arms. The only downside is the part count is a little higher. I think this one is worth considering as a possible replacement for the current prusa. With the use of a Sarrus linkage derived rising table, all linear bearings could be eliminated. Is itby martinprice2004 - Robots!
Re: Helium Frog HF06 "SCARA" Robot - 12 years ago
Yes the firmware is modular. It will be based on the delta robot firmware on my site here which is very basic but does work. It will just need a change of the equations in the delta routine to get it working. Ill also work on a few extra G codes and maybe add acceleration. The SCARA robot formulas are actually easier because the Z axis is conventional cartesian configuration. The delta firmwareby martinprice2004 - Robots!