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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: Full crosbraces for Prusa Mendel - 13 years ago
Nothing is ever as simple as in the text book. Theres a slight confusion here that corner to corner rods are the best solution, they MAY be better than the one in the original post, but they may be worse. There are several reasons for this. 1) It assumes steel is the same in tension and compression. This is approximately true for steel beams, but for thin rods. Euler Crippling Loads come into pby martinprice2004 - General Mendel Topics
Re: Getting started and looking for opinions... - 13 years ago
As you are coming from the CNC end of things and your priority is not self replication, you are looking for a "repstrap" machine. There are lots out there, but I suggest a good place to start would be the HydraMMM. Follow the link on the right of the page to the build blog. If you have a CNC machine have you considered using that. You only really need a heated bed, a wades extruder and say a jtby martinprice2004 - Reprappers
Re: Maybe a dumb question - 13 years ago
One shouldn't judge other peoples designs so harshly. We can all see improvements in a design its called "20/20 hindsight" I would say however that if you can avoid bridging and support material and avoid overhangs of more than about 60 degrees it will be printable by anyone even if they are struggling with setup which can only be a good thing. All the parts on a prusa and wades extruder can bby martinprice2004 - General Mendel Topics
Re: High Temp Heated Chamber Issues - 13 years ago
Maybe its the hobbed bolt and pinch bearing holding the heat as they are metal. Air cooling is very inefficient so maybe water cooling might be an idea. Just run an inlet and outlet tube to your extruder block. The extruder could have an internal pipe structure as this is quite easy to do in a reprapped part. The voids in the part would wrap around the areas you want to cool. You could have an eby martinprice2004 - Mechanics
Re: Full crosbraces for Prusa Mendel - 13 years ago
In the automotive field, a good test of a structure is tortional stiffness, where you fasten one end of the structure then apply a twisting load to the other to measure angular displacement (its often quoted as a measure of how good a chassis is). Perhaps this might also be a simpler way of getting a feel for how various designs perform against one another. The basic principle is shown here andby martinprice2004 - General Mendel Topics
Re: Maybe a dumb question - 13 years ago
This is not a dumb question. I think the part is supposed to be printed with your bridging parameters adjusted correctly, so the printer speeds up across the gap eliminating the sag. It helps to have a fan also cooling the part during printing. I looked at this part and saw the same issue as I haven't had much success with bridging setup in skeinforge. This is why I redesigned all the parts in mby martinprice2004 - General Mendel Topics
Re: Full crosbraces for Prusa Mendel - 13 years ago
Resonance? Try attaching a large mass somewhere to change the natural frequency. Or better still a large mass suspended in rubber attached to the frame. As an added bonus it apparently works quite well if your printing during an earthquake. How about putting 10mm od/ 8mm id tube around the main frame members with a washer and bolt either end. It would be a relatively easy upgrade to see if it iby martinprice2004 - General Mendel Topics
Re: Giving up on Makerbot... >:/ - 13 years ago
I started with a makerbot cupcake and spent a few months trying to get it to work. Its almost impossible without a heated bed and I had to rebuild the extruder many times. In the finish I had to remake a new extruder until I got it to work. I think the later cupcakes are better though. I have a Prusa now and it is much better than a cupcake....its in a different league really. I should have buiby martinprice2004 - General
Re: why acceleration? - 13 years ago
I just have a feeling that it may be something else other than this thats causing the issue. Please report back how this goes I am keen to see how acceleration affects the top speed of a machine. I have always wondered how necessary acceleration really is, particularly with very short moves on stepper motors with relatively light loading, a belt drive which removes some of the shock and positby martinprice2004 - General
Re: what electronics should i use? - 13 years ago
I have been using the RAMPS board on my recent robots and I must say they are really easy to use. The Pololu drivers are cheap and easy to fit and because they are separate from the board simple to replace should you damage one. Working with the Arduino to upload and modify firmware is also straightforward. I go for the built up boards as I am not very good at soldering and wouldn't attempt surfby martinprice2004 - Controllers
Re: Where are people? - 13 years ago
I was wondering where all the East of England guys were. It seem now there are a few builders around Cambridge. I live about 20 miles west of Cambridge (Near St Neots) so Cambridge area is Lstutehall, Bluesteel,Qbert,martinprice2004. Lots of interesting stuff on Bluesteel website, Check out my website www.HeliumFrog.com to see what I get up to.by martinprice2004 - United Kingdom RepRap User Group
Mounting a 608 bearing into a reprapped part - 13 years ago
I usually mount my 608 bearings in a 7mm wall plate and secure then with 3 bolts and washers in slots positioned around them as seen in the right picture here. These are 6mm bolts, but I would now use 3mm. Has anyone a different method such as cable ties, pinch clamping etc. which may be a better alternative?by martinprice2004 - Mechanics
Re: Symmetric belt-driven extruder to remove stepper motor from X carriage - 13 years ago
This is a neat design. I was doing a few calculations on weight saving which is your main goal here. The motor moves off the axis saving about 400 grams, but you do add 4 bearings and fasteners about 150grams. If you drive the axis directly with one of the belts and the extruder with the other, you eliminate 2 bearings on the carriage which is an improvement over your design. Overall though thisby martinprice2004 - Mechanics
Re: Pro's and Cons of various cartesian gantry layouts - 13 years ago
Going back to the various cartesian configurations. It is true that the each configuration will have advantages and disadvantages. I think it is important to consider where future reprap design is going and in particular what direction extruder development will be. For example. If you think multiple heads are the way, or large "inkjet type" heads may come about, you are probably best with a fiby martinprice2004 - Mechanics
Re: 8 mm Rods: Shafting Steel vs. Stainless Steel vs. Mild Steel - 13 years ago
Some interesting points here. My experience is that the stainless rods I bought (303) are a little harder than mild steel rod I bought from B&Q (Probably cheap EN1a 230M07) and also the surface finish is slightly better, but as you rightly pointed out it depends on grade and work hardening. Most bars are "bright drawn" which causes work hardening so the quoted hardness figures are a little miby martinprice2004 - General
Re: Threaded Inserts for Thermoplastics - 13 years ago
The soldering iron method sounds like it would work for harder or glass filled plastic. I think you might get into a sticky mess with ABS or PLA. It might be better to forget the heated route and go for a self tapping insert. There are hundereds of different ones, but probably ones with very coarse external threads might get you around the hole sizing problems that we have in the reprap communby martinprice2004 - General
Re: Impossible idea - 13 years ago
Unfortunately you won't be able to patent it anyhow as it has already been done. There is a video here showing how it works. I think this one is even made from recycled parts. Haircutting machineby martinprice2004 - Robots!
Helium Frog HF06 "SCARA" Robot - 13 years ago
I have just begun a new SCARA robot design, which will be reprappable. Heres the blog if you want to have a look and comment. HF06 SCARA I think it would be a useful addition to the reprap stable as it has features that the Mendel / Prusa doesn't have such as:- Tool changing becomes relatively easy as the area around the tool head isn't cluttered with the machine frame. A fixed work tableby martinprice2004 - Robots!
Re: Need help with SFACT! - 13 years ago
There was a major change in how the extrusion rate was implemented in Skeinforge 040 onwards. If you changed from an old version of skeinforge to a new one of SFACT the firmware extrusion variables may need resetting. See here for a discussion on the subject.by martinprice2004 - General
Re: Thoughts on Fill Algorithms - opinions welcome - 13 years ago
My thoughts The idea of perimeter printing a couple of layers sounds a good one to me, Rather than pour material in every two layers or so, you could perhaps conventionally hatch fill every couple of layers just with more material. This way it might be a little more controllable and easier to compute. I think skeinforge could implement this as there is an option to put a solid layer at intervalsby martinprice2004 - General
Re: Reducing microstepping options - 13 years ago
Yes I think this information would be useful. My original post was really intended to start a discussion on this and to see what information was out there. I also read the firmware forums here and there is a need to reduce the loading on the firmware side of things as well which reducing microstepping could offer. The link below shows some simple setups to measure torque, holding torque etc. whby martinprice2004 - Firmware - experimental, borrowed, and future
Re: Reducing microstepping options - 13 years ago
Hang on a minute. You said changing microstepping makes no difference, only to noise levels So now you are admiting that torque can change and you might have to revert to full stepping in some cases. You also say that there may be a small difference when stepping X8 or X16 in some cases. In addition you also admitted about a year ago that you have to set the current up on your drivers 1.4X toby martinprice2004 - Firmware - experimental, borrowed, and future
Re: Reducing microstepping options - 13 years ago
Thank you for the links it was very informative. It does appear that motor torque is sometimes unaffected by microstepping and at other times does get affected. It states that this is dependant on a few factors the major one seems to be the speed of the motor if I understand it correctly. It also appears that there are two components to torque. The drive torque (The torque available to do workby martinprice2004 - Firmware - experimental, borrowed, and future
Re: Reducing microstepping options - 13 years ago
Now you are confusing resolution with accuracy.by martinprice2004 - Firmware - experimental, borrowed, and future
Re: Reducing microstepping options - 13 years ago
nophead Wrote: ------------------------------------------------------- > That article you linked is nonsense. > Most stuff on the Web about microstepping is plain wrong. > So what your saying is an article in a respected machine tool design magazine by an engineer who designs them for a living is talking nonsense. As well as all the other articles I refered to. In addition the collecby martinprice2004 - Firmware - experimental, borrowed, and future
Re: Sprinter firmware, All 3 axis going twice the distance - 13 years ago
Yes I have a Ramps 1.2 board and have the same issue even though the jumpers are set to 16x. My motors are 1.8 degree steppers but run 8x microstepping. Perhaps you could also feedback how the machine runs to this reprap forum as it would be a help.by martinprice2004 - Firmware - mainstream and related support
Re: serial lcd - 13 years ago
Yes that would require less output pins by using the serial tx and would make sense as you have already bought the sparkfun kit. I drove a lcd directly from the arduino on my delta robot to report x, y, z etc. So if you want to have a look to see how simple it is have a look at the firmware here and a video of the machine here Be sure to write up how you get on as I am sure this would be of intby martinprice2004 - Firmware - mainstream and related support
Re: Prints stop after some unknown number of commands - 13 years ago
I was still getting a few stops during printing and have noticed that the Repsnapper "time to complete" bar does go to the end just before the print stops even though there is still lots of gcode yet to send. It also sends a M110 code to the machine at this point. Is the firmware thinking its the last line of code and stopping? As suggested by others here I switched to Pronterface Printrun on wiby martinprice2004 - Firmware - mainstream and related support
Re: Reducing microstepping options - 13 years ago
nophead Wrote: ------------------------------------------------------- > Reducing the microstepping does not make the > drivers run cooler. They are switching constantly > at a high frequency, even when the motor is > stationary because they are chopping to regulate > the current. > > Switching from 16x to 8x will just make the > machine a bit noisier, the torque and heaby martinprice2004 - Firmware - experimental, borrowed, and future
Reducing microstepping options - 13 years ago
My prusa runs a Ramps 1.2 board and when I first ran it up I assumed it was 16x microstepping, but quickly found it was printing twice the size, so set my firmware to 1600 steps per rev. (200 x 8) To cut a long story short my machine runs really well 8x microstepping, very quiet and the pololu driver heatsinks are cold enough to touch by hand when printing as they are effectively doing only halfby martinprice2004 - Firmware - experimental, borrowed, and future