Show all posts by user
Here's what I made, here's a photo, and here's a link to the [[page]] on RepRaps wiki!
Why use G code - 14 years ago
There are several projects on the forums to reduce the cost and complexity of the reprap electronics either by using the pc as host or reducing the size of the firmware so it fits in a smaller arduino. I have had a search through the forums but cannot see anyone who has suggested the following approach. Dont use G code to send to the arduino, but instead calculate the number of steps each motorby martinprice2004 - Controllers
Re: Im making a tripod - 14 years ago
My design for a reprap stype delta robot is nearly complete. If you want to take a look follow the link for a CAD image of the design. Any comments or suggestions would be welcome. I want to incorporate as much knowledge from here as possible before commiting to printing the parts. Helium Frog Delta Robotby martinprice2004 - Delta Machines
Re: Im making a tripod - 14 years ago
Viktor Did you develop any arduino software for the Delta robot? Is it available anywhere? I am just beginning a delta design and would welcome any hints. I have the design about 90% complete in CAD an will soon be reprapping the parts. I have worked out all the equations for transfering cartesian to delta coordinates, but if you have any C code that would be helpful.by martinprice2004 - Delta Machines
Re: Introducing The Mendel Uni-body - 14 years ago
This is really great work. I'm interested in how you moulded the parts for this design, were they cold cast? Plastic failures are not something you should be concerned with as it can all be overcome with careful design. Nylon glass filled plastic would be an option and has been in the automotive industry for years. You can fill up to around 60% glass. It does become a little brittle though anby martinprice2004 - General
Re: Dumb Electronics Question - 14 years ago
Printing Mosfets There are a few people doing experiments to make simple electronic components from readily available items. A transistor or mosfet is a simple gate device containing if my memory serves me right 3 layers, so much simpler than a microcontroller. It is not inconcevable that this could be printed on a reprap, perhaps doped and then overprinted with another layer. The component wouby martinprice2004 - General
Re: Dumb Electronics Question - 14 years ago
The reprap foundation has realised this shortfall in complicated electronics and I think the arduino mega is now the forerunner for the next generation electronics. Clone arduinos are seriously cheap so technology may overcome the cost or availability issue. Current reprap electronics are not easy to obtain, makerbot are nearly always out of stock, so the arduino system would help matters. I cuby martinprice2004 - General
Re: 95% reprappable repraps
- 14 years ago
The method of using pneumatics on a machine requires an interface to the electrical system. The computer or microcontroller uses electric and you somehow have to change this into a pneumatic force. Most valves use a solenoid to move a small piston. This movement is almost always assisted by air (its called piloting or a pilot assisted valve). From my experience a metal valve ceased to actuate atby martinprice2004 - General
Re: High Performance plastics and Automatic weapons - 14 years ago
Don't worry I am just working on a reprappable bullet proof vest. I shall post it up on thingiverse when its complete. I am having trouble though extruding kevlar....can anyone help?by martinprice2004 - Administration, Announcements, Policy
Re: 95% reprappable repraps - 14 years ago
In my days in the machine tool industry. I remember there was a French company called Telemechanique that made spool valves with plastic bodies and they were quite good and very compact. They did have rubber 'o' rings in them though for sealing. So what you are suggesting is definately possible. Most machine tools run at pressures between 80 and 120 psi and you can design plastic bodied valves toby martinprice2004 - General
Re: Dumb Electronics Question - 14 years ago
I did understand the difference. Unfortunately controlling a reprap is not a real time computing application. Real time computing as general rule involves systems that require virtually instant response from the OS. They also normally involve a feedback loop which is time critical. The Wiki article suggests such a system eg ABS braking where if there is a delay the system fails. The reprap machiby martinprice2004 - General
Re: Arduino - is it really needed? - 14 years ago
I just posted a link in another thread "dumb electronics question" perhaps some of you electronics guys could take a look and see if it would overcome the timing issues. The usb board you need is very cheap and so are the extra chips.by martinprice2004 - General
Re: Dumb Electronics Question - 14 years ago
With reference to C# Garbage collection. I think we really need to get a sense of scale here. Unless you are clearing huge swages of memory the delays will be very small and won't be noticed by a stepper motor program. Garbage collection also occurs in Visual C# when processor usage is less intense. It can be switched off if required and conducted at the programmers request. Modern PCs run manyby martinprice2004 - General
Re: Dumb Electronics Question - 14 years ago
I have had the same thoughts also. Why use a microcontroller when its sitting next to a computer that is miles better. It was no contest when PCs had parallel ports, as using the PC was the way to go, but now they only seem to have a USB port the issue of timing does arise and to many this is where their investigation stopped. There is a way however to get accurate timing as shown here with a sby martinprice2004 - General
Re: quality of items - 14 years ago
Whilst quality of items is important for some things, it is not that important for others. It all depends what you are making. I make many of my parts at 0.5mm layer spacing, I would go bigger if I could. I can produce a usable part quickly and the quality is good enough for any little project I have. If anything is a little rough a few minutes with a drill or knife usually sorts things out. Iby martinprice2004 - General
Re: Selective Thermal Sintering using DLP and instense, non-laser light source - 14 years ago
Perhaps a good start to the thread would be to provide a few links to some good sites so that we can all become familiar with the basics of the process. If the principle can be proved I'm sure there would be many here that would then carry on the work.by martinprice2004 - General
Re: Generational Degradation - 14 years ago
I did think inhibition sintering sounds a little wasteful, which is why I suggested a possible inverted process whereby the part material is doped with something to enable it to take more heat energy. I am still a little curious as to why salt is needed rather than the water being enough to take energy from the surface for evaporation. If you could avoid using salt solution and use water or mayby martinprice2004 - General
Re: Generational Degradation - 14 years ago
Sorry fgrams we seem to have completely hijacked this post! I didn't understand how the mask is made? Does it mean that you can only make what are essentially extruded parts or do you have to remake the mask every layer as the section changes? What is the mask made out of. Is it possible to focus infra red heat to a beam or through a small hole slot? Effectively producing a poor mans laser? Iby martinprice2004 - General
Re: Generational Degradation - 14 years ago
As you have all suggested FDM would seem to require other processes like milling or paste extrusion in order to make a machine capable of total self replication. This makes the machine more and more complex and raises ever increasing difficulties (The technology pyramid is the wrong way up!). I agree with Viktor that laser sintering would seem to be an easier route. I am surprised that this techby martinprice2004 - General
Re: Generational Degradation - 14 years ago
I also remember that "Moire Fringes" also called interference fringes is a method where you can use less accurate scales to measure more accurately than the scale itself. I think this is the way digital calipers work. Vernier scales do this also as used on an old micrometer or a slide rule. (Am I revealing how old I am here!) The side topic of extrusion nozzle manufacture. As far as I am aware iby martinprice2004 - General
Re: Generational Degradation - 14 years ago
This could be an issue, but is unlikely if multi point contact is employed. Two gears together could compound any errors, but pulleys and belts tend not to as the toothed pulley averages its error across several teeth as it wraps around. This is further assisted as has been mentioned by gearing in the mechanism improving accuracy. If I remember my history correctly, the first metal lathes were dby martinprice2004 - General
Re: RepRap using wax for making bronze molds? - 14 years ago
Sorry guys I mis read the original post. My apologies. I promise I shall go and sit on the naughty step for the next hour. Plastic masters are used for investment casting as is foam, wood and frozen mercury. Perhaps trying an abs or pla master would be the thing to try first.by martinprice2004 - General
Re: RepRap using wax for making bronze molds? - 14 years ago
The lost wax process (investment casting) could be used for reprap parts, but unfortunately it won't improve your productivity. It can effectively take a plastic part or wax part and convert it to a metal one, but as a general rule both the master part and the mould are destroyed in the process. So you only get one part from one part. It is pointless trying to make a wax part on a reprap then inby martinprice2004 - General
Re: I Need More Motor Torque - 14 years ago
I have my machine more complete now and got the software fully installed. The axes are fairly free running, but not ideal. The torque supplied by the motors and easydriver boards is still proving to be a problem however. The easy driver boards are Micro8 stepping, which is also I believe may reducing the torque. My power supply is only an old 250 watt supply, but the problem occurs even if I dby martinprice2004 - Controllers
Re: cheap low profile fasteners for joining multiple parts - 14 years ago
This is a nice idea, but sounds a little like using a sledge hammer to crack a nut. Joining two plastic parts is done regularly in industry. The most common method is vibrational welding. The parts are vibrated together and generate heat at the interface and weld together. Its a variation of friction welding. Its perhaps a little complex for hobby applications but could be adapted. If you look uby martinprice2004 - Mechanics
Re: Hydra-MMM Software and Firmware Release! - 14 years ago
Clayton I have been using you firmware for my machine and it is really good . I did a little debugging now my machine is a little more complete and found a few areas that need attention. I don't know how to contact you other than through this forum, so here goes. Firmware 1) The following integer variables need to be larger otherwise when using metric units and microstepping they can go out ofby martinprice2004 - Shape Deposition Manufacturing Working Group
Re: Why Not use Nylon? - 14 years ago
What about spraying one of the chemicals on the surface and then printing the other rather than printing both. Or alternatively printing alternate layers of each chemical. This may make the print head design a little easier than a dual nozzle/ mixer. Can you buy the two chemicals easily?by martinprice2004 - General
Re: I Need More Motor Torque - 14 years ago
I have turned the pots up to maximum and they still were not giving enough torque. My machine does use lead screws and plain bushes, so is not exactly the same as a reprap, but the mechanism is quite free running. Late last night I rewired my electronics to supply 5 volts as opposed to the 12V and to my surprise the motors seemed to work much better and didnt miss a beat until I put the axis feby martinprice2004 - Controllers
I Need More Motor Torque - 14 years ago
I am having trouble driving my work platform on my home made CNC/rapid prototype machine. I'm using an Arduino Mega, EasyDriver 4.2 and stepper motors from Zapp automation. The axes tend to stutter and stall even when turned up to the maximum. I run them froma 12v motor supply. Are the Easy Drivers limiting my motor torque as I believe they are rated to only 0.75A? would the Pololu drivers giveby martinprice2004 - Controllers
Re: Arduino Mega - 14 years ago
I know this is a simple question, but what would happen if I just installed the latest makerbot or reprap firmware into an arduino mega and connected the steppers (via stepper driver boards) up to the correct pins on the arduino mega board? I understand I may not have extruder control, but would the steppers respond to XYZ G code? How does the arduino mega recieve its serial G code data when ruby martinprice2004 - Controllers
Re: The Reprap's impact on the environment - 14 years ago
Forrest Higgs Wrote: ------------------------------------------------------- > martinprice: You've made some interesting > assertions. It would be nice to see some > published numbers, or any numbers for that matter. > Don't forget to factor in transport and > distribution costs into the manufacturing costs > incurred by your "extremely energy efficient" > factories. Thby martinprice2004 - General