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Re: Pre-wired drive unit
Message: 2I've built a few for people have found it to be VERY time consuming to wire up. HOPING that there may be a market for such a thing and with some interest from a few people already, I'm nearing completion of a set of circuit boards. ( As I've done in the past, complete details should be freely available for those who wish to do it themselves ) There will be three boards inside the controller. Board one will mount almost anywhere on the rear panel, and will have the following connectors a DB 25f for direct connection to the PC a DE 9m for an optoisolated EStop connection a DE 9m for Home/Limit switches a DE 9f for external control of Spindle, Coolant, etc. and the following electronics my Error/Reset controller a 5 volt switching power supply, so that power from the PC is not required Board two will have axis enable switches and status LEDs Board three will be mounted most accurately on the rear panel and will have the following connectors four MIL-9s for connection to the encoders and motors four pairs of power&ground connections/solder points for Gecko power and the following electronics four EStop relays four optional differential receiver circuits four 470uf caps four Gecko "load" resistors four optional "brake" resistors four .200" pin headers for direct connection to the Geckos Once the chassis is accurately drilled, assembly is 1. wire up power supply or simply hook up one of the commercially available supplies 2. fasten PCB 1 to rear panel 3. fasten PCB 2 to front panel 4. fasten PCB 3 to rear panel 5. lay Geckos on bottom panel and slide towards PCB 3, such that pin headers on PCB 3 slide into Gecko connector. 6. fasten Geckos to bottom panel 7. tighten Gecko screw connections 8. run ribbon cables from PCB 1 to PCB 2 and PCB 3 9. run power and ground wires to PCB 1 and PCB 3 Total time to assemble, once the chassis is ready, should be about 20 minutes, with not a single "wire" going to a Gecko. All Gecko wiring is "automatic". Price is hard to say, as PCB costs are greatly influenced by the number of boards ordered. Worst case, about $400.00, assembled and tested. Best case, maybe $325.00. Any interest ? Alan -- Alan Rothenbush | The Spartans do not ask the number of the Academic Computing Services | enemy, only where they are. Simon Fraser University | Burnaby, B.C., Canada | Agix of Sparta |
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Re: Stepper motor speeds
It is not as easy as just looking at a particular metal and getting a
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required speed and cutting force. As an example, if I cut a piece of aluminum on my Bridgeport with a 1-1/2" 4 flute carbide insert cutter I may use a feed of 50 ipm. If I cut the same material on my Sherline with a 1/4" 2 tooth HSS cutter 10 ipm will be more appropriate. Not only are the speed vastly different, but so are the required forces. So, it is not just material but also how much horse power you have, how rigid the machine is which will limit the size of a cut you can take, etc. While you can take the engineering approach to this and calculate everything a much easier approach is to just follow what others have found to work. If I remember correctly you are setting up a mill/drill or a Shoptask? If so just use some low inductance NEMA 34 motors in the 400 - 600 in/oz range and you will get great performance that is in line with what the machines capabilities are. Lots of us have done it and we know it works. Now if I was designing this to produce a number of these machines I would get a lot more worried about actually calculating it all out so I could better understand where I can save a little. Tim [Denver CO] -----Original Message----- |
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Re: Stepper motor speeds
Marv Frankel
Dave,
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Thanks for the information, and the reference to Mariss's message. I can understand most of it, but his reference to "push" has me a little confused. The formula for "push" is clear enough, but how do you figure out how many inches/minute or pounds are required? Don't both factors vary with the material being milled? If that's the case, it would be helpful if someone posted a chart with the speed & lbs. for various materials. It might help me to make an intelligent decision. Marv Frankel Los Angeles ----- Original Message -----
From: "turbulatordude" <davemucha@...> To: <CAD_CAM_EDM_DRO@...> Sent: Sunday, November 03, 2002 8:26 AM Subject: [CAD_CAM_EDM_DRO] Re: Stepper motor speeds Hi MArv,aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill |
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Re: Polar Coordinates CNC?
Ken,
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Here is one reason; it's called necessity :-) I wanted to make some decorative wooden gears that appeared to be too big to do on the Sherline. But, by mounting the blank on the rotary, I only had to access from the center of the rotary to the outermost point on the circumference yet could still cut anywhere on the full disk. There may be better ways, but I just drew it up in the normal X-Y fashion and wrote up a small VB app to convert the Y's to C's. The only tricky part was that a new feed rate has to be entered for each block, due to the way that my controller (CNCPro) handles rotary feeds. So, to answer your question, it basically doubled my capacity for this rather unique job. Hope this helps, Al Lenz --- In CAD_CAM_EDM_DRO@y..., Ken Jenkins <kjenkins@b...> wrote:
Interesting idea ... but why? It seems to me the particulars |
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Refitting a Lynx
Guys,
I have a chance at getting a good deal on a burning table but am in need of some help. The rig is an Union Carbide CS-56 table with the original GE amps left on it, and a Lynx Technologies controller scabbed onto it. The GE amps are smoked and I need to know what (if anything) would be a reasonably easy hook up to replace them? Geckos? The motors are Balder dc servos at approx 80 volt, 5A. Any help greatly appreciated. Iain |
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tool download; steps to removing a virus
A few people on this list are infected with an email virus,
W32.Yaha.E@mm. W32.Yaha.E@mm is a mass-mailing worm that sends itself to all email addresses that exist in the Microsoft Windows Address Book, the MSN Messenger List, the Yahoo Pager list, the ICQ list, and files that have extensions that contain the letters ht. The worm randomly chooses the subject and body of the email message. Depending upon the name of the Recycled folder, the worm either copies itself to that folder or to the %Windows% folder. You can go to ml for more information. They have a tool there that you can download to check your system, .tool.html Please use it, Thank you. ¤?°缚°?¤?,??,?¤?°缚°?¤??¤?°缚°?¤?,??,?¤?°缚°?¤??¤?°缚°?¤¤?°缚°?¤ robert weiss bobweiss@... [Non-text portions of this message have been removed] |
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Re: Has anyone built an SPC display for Digimatic scales?
Chris Baugher
On Fri, 1 Nov 2002, John A. McFadden wrote:
Would you happen to have wiring diagrams that could use regular momentaryUmm, well sort of. I have a partial schematic but it's not complete. I'm using an Atmel ATMega8 MCU to decode the data stream and display the numbers on an LCD. The type of switches doesn't really matter as long as they are momentary. Also the code isn't complete either. When I get this thing closer to completion I'm planning on putting it all up on the web. Hopefully that won't be too long from now but it's hard to say. C| |
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Re: Question Concerning API CMD-260 Drive Current Setting
Not sure of the exact motors you are using, but if it is the same
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Powermax II motors I have on my Sherline than the 2.3 amps is the setting without any additional reduction if you want the absolute maximum low end torque. I am running then at 1.75 amps if I remember correctly as I don't care if I lose some low end torque (I have plenty) and it keeps everything a little cooler. You could use 1.5 and I bet you do not see any performance difference. There is no need to run them at the absolute maximum possible most of the time. Tim [Denver CO] -----Original Message-----I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner |
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Re: Polar Coordinates CNC?
Fred Smith
--- In CAD_CAM_EDM_DRO@y..., "wenger2k" <wenger2k@y...> wrote:
The application would be the same as any other - i.e. router/plasmaapproach given that you eliminate many of the most expensive components ofthe system (the long axis Why hasn't this been done before? I don't know - I expect that theIt's been done many times. It is referred to as a rotary axis. If a rotary axis is oriented parallel to a spindle (Z), it is identified as a C axis. The complete range of movement can be defined as X-Z-C coordinate triples. Since G-code by definition is the tool movement, the entire coordinate system is covered by this. Several of the G- code intrepreters can output rotary axis code. The problem with this method of control is that the linear movements by definiiton are approximated by tiny arc movements. Since most movement is linear, the programs become quite large. 10 years ago it was a no-brainer as the controllers could not process large programs. Today it may be economically feasable to produce rotary code (polar to you) that can be processed, and the result could be a machine with a linear and a rotary axis. One draw back is that as the radius increases in size, the machine accuracy decreases. This is not the case with dual linear machines. a 3 place decimal degree is much more accurate at a 2 inch radius than it is at a 20 inch. You may need to spend more than you would think to get a reasonable angular resolution at the longest radius. A 2000 line encoder, a 4 foot diameter would be 150.8 circumference. yields .0754 inch per encoder line. This would not be too practical. However, IF, (very big if) you could get a decent circular rack at 4 foot diameter, you could get excellent resolution from a stepper motor. Also might get some decent resolution from a pully or gearbox setup for a center drive. It's almost intriguing enough to start throwing a prototype together. ;-) Best Regards, Fred Smith - IMService |
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Re: Polar Coordinates CNC?
The application would be the same as any other - i.e. router/plasma
application (4'x8' as practical size for discussion purposes). I would think that Linear moves in polar space would be roughly the same and no more complicated than arc/circular moves in cartesian space - would they? I think that a polar machine could be a more cost effective approach given that you eliminate many of the most expensive components of the system (the long axis). Parallelism is eliminated as a requirement which generally requires you to do "special" things to tie the parallel sides of a large gantry style machine together either via encoders or long belts if using multiple drives. You lose a certain amount of rigidity with a gantry machine that either must be made up by stiffer slides or beefier components on the gantry itself. All of these result in a large heavy gantry which of course requires a larger motor(s) to drive. It looks to me like a lot of these issues can be avoided on a polar based machine as there is a single pivot point and therefore single drive point. A very large machine would have to either have an extremely heafty arm or would have to be supported on the outer end of the boom. So significantly larger sizes likely are not practical. I think the biggest problem with a polar machine is one of accuracy... i.e. the accuracy will "expand" as you go out from the central pole. That's ok as long as you can get sufficient accuracy in towards the pole/pivot point. This factor would also likely dictate the largest practical size. As a test application I was thinking of a 4x8 application using 2 quadrants. 4' x 1.414 (2*sqrt (2) ) makes a boom of 6' able to cover the entire area of a 4'x8' sheet. Why hasn't this been done before? I don't know - I expect that the cartesian basis of g-codes themselves have preselected this to a degree. A Polar router has some similarities to a hexapod in my mind in that it requires ongoing trig conversion for each axis/movement. But it's obviously been handled for hexapods which I think are significantly more complicated than the polar option. So it seems doable... Lee Wenger Denver, CO |
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Question Concerning API CMD-260 Drive Current Setting
I have a question about the appropriate current setting on my API
CMD-260 bipolar drive. I will be using a Powermax II Bipolar Stepper motor which is rated at 2.3Amps per phase when the phases are wired in series. From data gathered at the API website it appears that the proper drive current setting for this motor in a series configuration is calculated as: 2.3Amps x 0.707 = 1.63Amps . Therefore, a conservative drive current setting of 1.5Amps should be selected. I don't know how the API conversion factor of .0707 was derived. If I am correct, a dip switch pattern of '10100' should set the drive to 1.5 Amps. Is this the correct drive current setting for this motor? If not, what would the correct setting be? Any help will be greatly appreciated. Thanks - Dan. |
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OT: (was Re: FAQ pages relocated
turbulatordude
Hi guys,
this is pretty far off topic, but I'll put in my two cents. I prefer a page that offers a button to let the person go to the home page. or to the main topic page if one is levels deep in a thread on the site. Dave --- In CAD_CAM_EDM_DRO@y..., "Tim Goldstein" <timg@k...> wrote: Frank,way I want to do it for my reasons. If you don't like it don't go there.which the "back"keep sending you back to the same page. It is BS !! I am using canicon and right click. This will bring up the history menu ,..you pagenow go back to other pages. I can't stand when a programmer be aman and tell him to remove this code.I consider this to sister site to the CCED group, as many of the same members arethere, for OT subjects, that are not allowed on the CCED list.THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ |
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Re: Polar Coordinates CNC?
Ken Jenkins
Interesting idea ... but why? It seems to me the particulars
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of the math involved would not make arriving at the end use coordinates any easier. Do you have a particular application in mind? I'm just curious why Polar over Cartesian would be any better and if so why it hasn't been done? Ken Message: 9 |
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Re: Stepper motor speeds
Marv,
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Now sure what you are saying by "I haven't heard any discussions about speed ranges and how they're controlled.". Speed is controlled by how fast you feed your drive pulses. The higher the frequency the faster the speed until you run out of torque on the motor/driver/power supply combination. Stepper motors have a torque curve that is like a cliff (OK more like a very steep face, not a vertical face). At low speeds they are on the plateau and have a lot of torque. When you hit the knee where inductance becomes the limit and not the current limit of the drive the torque starts to fall off very rapidly with increasing RPM. So to go fast you have to use a motor with a lot of excess torque at low speeds. Gearing a stepper only makes reaching a high RPM harder as it required more RPM. You will get higher feeds most often by reducing the gearing and using a high torque motor. The RPM you will get with any motor is quite variable depending upon a lot of factors. The primary ones are the torque curve for the particular motor, the voltage you are driving at, the smoothness of your pulse stream, and how you connect the motors. Most motor manufacturers will offer the same size and torque motor with different winds. Some will be capable of higher RPM. The higher the drive voltage you can use the faster you can go. As you get up towards the high end for a particular motor the evenness of the pulses becomes a big factor. Basically a bunched up pulse is really a rapid acceleration that you may not have the torque to make. How you connect the motors will affect the inductance and there by have an effect on the speed. If the manufacturer has a torque curve for series and parallel bipolar you will see this right off. So after all this rambling, if you need 150 in/oz to retract and you want to be fast then put on a 400 in/oz plus very low inductance NEMA 34 and run it direct drive at as high a voltage as you can. Tim [Denver CO] -----Original Message-----I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner |
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Re: Stepper motor speeds
turbulatordude
Hi MArv,
check post 45509. I think that covers it pretty well. The small section that may be direct is : quote : (2) Steppers have lots of torque at low speeds and very little torque at high speeds. This is a good thing. Work is done at low speeds where you need a lot of torque; high speeds are usually "rapids" where little torque is needed. As a rule of thumb, steppers are pretty much out of torque (rapids) at: Size 42, 300 to 600 RPM, 800 in-oz or more low-speed torque. Size 34, 600 to 1,200 RPM, 150 to 450 in-oz low-speed torque. Size 23, 1,200 to 2,400 RPM, 50 to 150 in-oz low-speed torque. Size 17, 2,400 to 4,800 RPM, less than 50 in-oz torque. end quote There is more on gearing and stuff. Dave --- In CAD_CAM_EDM_DRO@y..., "Marv Frankel" <dcdziner@p...> wrote: Guys,respect to required torque, but I haven't heard any discussions about speedthe quill. My down feed requires almost no torque, but retracting |
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Re: toolpath creation problem or wrong interpretor setup?
Ian W. Wright
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----- Original Message -----
From: "Alan Marconett KM6VV" > Yeah, like the 7BA carbon steal tap (from England) I just broke! And IThis is one of the mysteries of life - you get crappy taps from England and all the cheap and nasty ones I buy here are from the US!!! There must be a lesson to learn here..... Best wishes, Ian -- Ian W. Wright Sheffield, UK The following added for automatic email harvesters! abuse@... abuse@... abuse@... abuse@... UCE@... abuse@... abuse@... |
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Re: Polar Coordinate based CNC
galt1x
Most Fanuc type controllers have a G code associated with polar
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coordinates G15 polar system off,G16 Polar system on, this typically deals with X=Radius and Y= Angle of hole from O (pivot point) which is the last point programmed before G16 is called and a Call of G17-18-19 to select the plane you are working in G-17 equals XY. This situation would also be a perfect application for a macro since polar coordinates typically use the same parameter values as a fixed cycle X,Y,R,Z,F etc.and the macro could be used without having to have the Polar Coordinate option involved. Paul E. Killoy --- Original Message -----
From: "Raymond Heckert" <jnr@...> To: <CAD_CAM_EDM_DRO@...> Sent: Saturday, November 02, 2002 6:15 PM Subject: Re: [CAD_CAM_EDM_DRO] Polar Coordinate based CNC As it happens, my SHARNOA CNC Vmill uses Polar coords foraol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill |
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