Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- CAD-CAM-EDM-DRO
- Messages
Search
|
Re: programs to write G-code
Jon Elson
I have put some programs that write G-Code for common
machining operations on my web page. Take a look at The programs are in C, and I've made them as portable as I can. They should run undel Linux with Gcc, or with MS-DOS and the Microsoft C compiler, or Windows xx, with Borland C. If you have trouble with them, let me know. I will be adding some more programs as soon as I get them converted. Jon |
|
Sharp manual wanted
Jon Anderson
Rather off topic, but with the expertise I see here, I might be asking
the right crowd. I bought a couple Sharp PC-1261 pocket computers with the CE-125 cassette recorder and printer at an auction recently. Need a manual at least for the computer, hopefully for the printer/cassette device too. Willing to swap one of these, with case, and a box of paper rolls, for a copy of either or both manuals. The unit I'd swap has no PS but it's an 8.5V 350 ma unit, and it comes with the original case, all in VG condition. It works, and prints, but don't know how to program it and don't have any tapes to verify that function. Anyone? Thanks, Jon |
|
Re: re vac forming
Jon Anderson
MIADsgns@... wrote:
Any suggestions on buiding the pump with meter, sources forI don't see any reason you can't use that tank as a vacuum plenum. Don't know how many inches of vacuum you can pull with a shop vac, but the tank will help with volume. Valving to take the shop vac out of the loop could be a simple PVC ball valve from the hardware store. Costs should be reasonable. Used ought to work just fine if you can find it. You can tolerate a slight leak here, you just don't want a high vacuum/low cfm pump trying to suck air back through the shop vac while it's running. Some old friends have a business in town (Maier USA) making accessories for dirt bikes and ATV's, vacuum forming plastic. It's a trip watching a droopy sheet of plastic turn into an ATV seatbase/fender in a matter of seconds! Their Thermwood 5 axis gantry router is pretty neat too... Jon |
|
Re: re vac forming
Tim Goldstein
Mario,
toggle quoted message
Show quoted text
I looked in Don Ross's newest book "Flying Models Rubber, CO2, Electric, & Micro Radio" and he has some pictures and explanation about a vacuum forming machine / kit made by Douglas E. Walsh, 272 Morganhill Rd., Lake orion, MI 48360. Looks like a very nice setup and it can be gotten as a 2 stage unit. I searched for a number on the ATT web site and got what looks to be a direct match with a phone number of 248 391 8290. Hope it helps, Tim [Denver, CO] -----Original Message----- |
|
Re: Installing rotary encoders
Tim Goldstein
Don't know about Bobcad, but I am using Vector to generate g-code for use in
toggle quoted message
Show quoted text
EMC. I have been very pleased with what Vector offers and as I get use to what EMC wants in the way of g-code I am having no problem getting Vector to produce a code that will work. go to (the US distributor) and check it out. You can also get some more info at (the developer). Tim [Denver, CO] -----Original Message----- |
|
Re: MaxNC modifications
Jon Anderson
Tim,
Will have to sit down with my dad and gather up the details, but here's what I can tell you right now. Not sure what you mean by controller, Ah-ha communicates directly with the stepper drivers via a special card. Power supply is 40 volt more or less, unregulated, based upon the schematic supplied by CyberPak for their drivers. Dad built the PS, I'll get details from him. Don't recall motor specs, will have to look them up again. Think they are rated for 5 amps, we are running about 3 now, or so we think. That is based upon the current limiting resistor. Dad thinks we're not getting full power to the motors and tried to measure amp draw INTO the drivers, came up with something like .5 amps draw at rapid (40"/min). However, it's a chopper driver, not sure if he's checking properly. I've written little test routine programs. Single axis linear moves, looped and run for 5-10 minutes show no lost steps. Interpolated linear moves (XY) show no lost steps. Circular interpolation seems to be the problem, but not always. My dad machines little resistive elements for a customer of his. These are generally under 1" dia and we run multiples of up to 8 at a time on a custom pallet setup. We've tried using G92 to set offsets for each nest, no subroutines; G92 with subroutines; G91 with and without subroutines; and if a particular job is going to show lost steps, it doesn't seem to matter how we approach it. Some parts do not lose steps. Each part will show a different pattern of lost steps. The pallet base has a .500 dia hole that we indicate from to establish datum, all pallets and all programming is referenced from this hole. It's real easy to drop an indicator in and check for lost steps. For example, one particular part run in multiples of 8 parts per pallet might show .0013 lost in X and .0003 lost in Y every for every pallet load. With the tolerances on this job, Dad can let this accumulate over two pallets before having to rezero. This is so consistent that he stopped checking after every two pallets and simply would jog X.0026 Y.0006 and rezero. After running several hundred parts, he'd check with the indicator after the last two pallet loads and be off exactly .0026/.0006. (I don't recall exactly the sign (+/-) of the error or corrections, but the numbers are real close to what he runs into) This is with a program that does not use G92, it's done with geometry in a subroutine, we move to a set entry point, enter the subroutine, enter G91 and machine features, then back to G90 and exit the subroutine. We lose NO steps in the Z axis. Motors are wired with shielded cable, grounded at one end to the motor PS ground. Logic lines are also shielded cable, grounded at one end to the computer ground. Care has been taken to keep power and logic lines well separated. If I didn't mention before, we've also run the MAX software on two different computers, a 486-33 and 486-66 with identical results. I'm close to getting my Cyrix P200 box done and will try the Ah-ha from it, but don't think that's going to solve the problem. Ah-ha warns about possible rounding errors and recommends programming to 4 decimal places. I edited a problem program to accomodate this and there was no change in the lost steps, so that's not likely to be the problem. I printed your message, when this gets back to me I'll print it as well. Dad will be by tomorrow and I'll give him both copies to go over and fill in any details I missed or don't know. We would both LOVE to solve this problem. Dad's good with basic electricity, but we are both stumbling in the dark on this, and it's getting expensive running around buying stuff trying to fix the problem. As for desired speed, would like to see 60"/minute. This was part of the reason I went with 16 pitch screws. I can accept the slight loss of accuracy, the tradeoff is that for a given linear velocity we are running the motors 20% slower. I may be all wet, but my seat of the pants guess was that we were coming out ahead over a 20 pitch screw by keeping the motor down in a broader part of the torque curve. I have some top quality linear rail bearings and ballscrews, and want to build a CNC conversion for my Hardinge. However, I have a hard time justifying the time and expense in finishing it with the lost steps we are getting. Even a single lost step per part would quickly cause major problems in the X axis of a lathe. Thanks, Jon (who btw, is highly impressed with the quality and quantity of posts to this list!) |
|
Re: re vac forming
Jon Anderson
Rough pumping can be done with a vacuum, and if you want to achieve
higher levels of vacuum, you can make a vacuum pump out of an automotive air conditioning pump. If you have a gage and can tell how much vacuum the shop vac can pull, you can run both at the same time and valve off the shop vac once you hit it's limit. If you don't, the other pump will be working against it. Jon |
|
Re: EMC
Tim Goldstein
Dan,
toggle quoted message
Show quoted text
Haven't heard any more about your EMC adventures. Have you loaded up the most recent version? Are you using it to make any parts yet? How is it working for you? Tim [Denver, CO] -----Original Message----- |
|
Re: MaxNC modifications
Tim Goldstein
Jon,
toggle quoted message
Show quoted text
I am sure you said, but what are you using for a controller? How many amps are you running to the motors and at what voltage? What is the volt & amp rating of your motors? What is the max feed rate you are trying to achieve? I think you can safely assume your lost steps are not due to the software at this point. From my playing with a number of software products I have pretty well come to the conclusion that if you are having lost steps it is not the software that is usually at fault. Do you have lost steps even at very slow feeds or are the lost steps most common at fast rates? The torque curve on a stepper falls off very rapidly with increasing RPM, so if you try to go too quickly you can easily get to the point of having too little torque to get the job done even with very large motors (actually, lager motors tend to drop off in torque faster than small ones and turn less RPMs). You can also have a problem if you have a very slow acceleration rate and your motor hits a harmonic in the ramp up. Often if you increase the acceleration you can get past the troublesome RPM without losing a step. A problem I had that drove me crazy was phantom steps. It seems that RF off the drive circuitry was inducing a signal into the step wiring on one of my axis. It was manifesting as lost steps when it really was unwanted steps. I ended up curing this by shielding the wires in a wrap of aluminum foil and grounding it at one end. Maybe you could also use ferrite filters?? (can one of you electronic gurus help explain if this would be a useful method? Jon, Mo, ?) I am sure with the help of people on the list we can figure out why you are losing steps and get it fixed. Tim [Denver, CO] -----Original Message----- |
|
EMC API?
Ron Ginger
I am very interested in EMC. Id like to tinker with the GUI part of the
system- Ive done a Mill Power kind of clone alerady under Win95, Id like to move that to EMC, maybe with Tk or Java. I assume there is a programmer interface- API- soewhere in EMC that can be used this way, but so far I havent found any docs about it. can soeone give me a pointer to the right docs? What seems to be really missing to me is a sort of overview doc that describes all the pieces and how they work together- the WEB page junps right to a description of an .ini file and lots of gory details, but never explains the basic structure of things. ron |
|
Re: Problems with linux 2.2.10 + beta5 + emc-14-Jun-1999 - anyone ?
David L Anderson
Also Be careful with the release of rt-linux you use. I had problems with
Ver1.1 for 2.0.36 kernels and had to drop back to ver 0.9J which works fine dave It is my understanding that EMC is currently set up for the 2.0.36 kernel and not yet tested or "supported" on 2.2.x. I am running EMC using steppers on RedHat 5.2 with the 2.0.36-7 kernel and it builds without errors and runs fine. |
|
Re: MaxNC modifications
Jon Anderson
Andrew Werby wrote:
[What is the advantage to using Aha software on the MaxNC, over using theirStock setup way too wimpy and slow. While I'm sort of playing around with my MAX, I do use it in my business, and my dad uses it a lot (learning CNC in his 70's!) for some commercial work he does. We needed more performance. Tried the step/direction version with Cyberpak drivers and MAE motors and found we were losing steps. Bought the PacSci motors (from Bill Griffin, used, he has no more...), still losing steps. Bought Compumotor drivers (brand new, obs stock) from a motion control outfit in Florida (can dig up the name and URL), still losing steps. Tried Ah-ha software both to try and cure lost steps, and for a better interface, better handling of radius comp, and the ability to search directories for files and not have to dump out of the program just to look up a filename. Still losing steps btw, and have not had time to dig deeper. [Were these easy to mount, or did you need to machine new mounting plates?Plates use existing holes in MAXNC. Motor attaches to standoffs to accommodate helical couplers. [Where did these come from? Are they what Aha recommends?]Ah-ha was the last item purchased, I'm sure they'd prefer we had bought their whole setup. Maybe we should have... motor mount plates with preloaded ball bearings toFabricated the plates and the shaft. Leadscrew attaches to the shaft same as stock on the MAX. Screw side has hex for wrench, other side has 5/16 nylock nut to adjust play in bearings. Acme screws, and an attempt to cure backlash. Mostly successful. Nut screws into 1/4" AL plate that in turn is screwed to saddle. These nuts are available in V-thread, so you could fit them to the stock screws EXCEPT that they mount outside the saddle so screws must be extended or you lose travel. [Do you think they would fit a stock zero-backlash nut?](referring to the Thomson econo ball screws) No, probably not. If one wanted to play with ball sizes, one could probably get down to little or no backlash. For the size machine you are thinking about, you will want the larger 5/8 screws that Dan mentioned. The small screws over long lengths can whip at higher rpm, and buckle under compression. They would be fairly easy to adapt to the MAXNC and could be fitted to a Sherline if one had access to a full size mill for the modifications. Would be very tight however. These little ballscrews might also work well to CNC a smaller lathe. The sample I got is useless for any CNC testing as it's too short, but I'm going to purchase a longer screw and two nuts to play with. Control systems? Heck, wish I knew. Still having minor lost step problems. Wish I had a local expert that could come over and tell me what I've done wrong... For econo linear bearings in a router application, personally I think I'd look around for some surplus Thomson ball bushings and fully supported rails. |
|
Re: New member, something interesting
Jon Anderson
Dan,
Thanks for that info, those are a good deal. Most anyone building a custom machine probably has plenty of room for a 5/8 screw. Still, for smaller machines and for budgets that can't justify miniature NSK ballscrews, these might be worth looking into. Jon |
|
Re: re vac forming
Thanks Tim,
My own search brought me to an excellent source of publications for making hard to find items such as Injection molding, vac forming machines, etc, etc. Lindsay Publications. The flyer I have its Called, Secrets. (815) 935-5353. It includes the book by Douglas E. Walsh. For anyone else interested in making theuir own stuff, this is an ecellent source. Mario |
|
Re: re vac forming
In a message dated 6/16/99 12:42:58 AM SA Eastern Standard Time,
janders@... writes: << Rough pumping can be done with a vacuum, and if you want to achieve higher levels of vacuum, you can make a vacuum pump out of an automotive air conditioning pump. If you have a gage and can tell how much vacuum the shop vac can pull, you can run both at the same time and valve off the shop vac once you hit it's limit. If you don't, the other pump will be working against it. >> Any suggestions on buiding the pump with meter, sources for the meters, hardware etc.? I have a used empty helium tank the type you buy at Toys R- Us, the instruction s that come with the tank says it can not be used to refill, can this tank be used for air/vacuum tank? How? Thanks, Mario |
|
Re: re vac forming
In a message dated 6/15/99 7:40:02 PM SA Eastern Standard Time,
footman@... writes: << if you are looking for a good vac source, go to a local dairy farmer (if you have any around) - apparently the pumps they use for their milking machines can be easily modified - also, how thick is the silicone membrane you are using - obviously the thinner the material, the more intimate it will be against the mold >> Thanks Chris, I am using a rubber strip around the perimeter top edge of the perforated table. The rubber strip is the stuff you purchase here in Chicago for weeather proofing doors. About 1/16" in thickness by 1/2 " wide, works fine once you get the frame lined up with the table. I have seen photos of vac forming machines with a hand pump mounted on the vacuum box, similar to the ones used for inflating bicycle tires the type you would stand on with your two feet, with a T handle. I'd like to know how this is installed and how it operates, not sure how it all works with a shop vac, does it draw more vacum after the shop vac is turned on? More info on this set up would be greatly appreciated. Anyone? Thanks, Mario |
|
Re: Problems with linux 2.2.10 + beta5 + emc-14-Jun-1999 - anyone ?
Tim Goldstein
It is my understanding that EMC is currently set up for the 2.0.36 kernel
toggle quoted message
Show quoted text
and not yet tested or "supported" on 2.2.x. I am running EMC using steppers on RedHat 5.2 with the 2.0.36-7 kernel and it builds without errors and runs fine. Tim [Denver, CO] ----- Original Message -----
From: Max Heise <mahe@...> To: <CAD_CAM_EDM_DRO@...> Sent: Tuesday, June 15, 1999 4:49 PM Subject: [CAD_CAM_EDM_DRO] Problems with linux 2.2.10 + beta5 + emc-14-Jun-1999 - anyone ? From: Max Heise <mahe@...>linux-2.2.x and the rtlinux patches for new kernels from ftp.rtlinux.org ?discussion of shop built systems in the above catagories. To Unsubscribe: |
to navigate to use esc to dismiss