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Re: CPNC
Ron Ginger
I think the point Fred is trying to make is that CNC is not always the bestThis is simply because Fred is selling the wrong software for this problem. Yes, he is completly correct that using a CAD/CAM system to do simple operations is slow. Thats my point entirely with CPNC- use a system DESIGNED to let you do simple things on a CNC machine. When/if you need to do complicated things use a CAD/CAM system. I have a friend with a big Lagun Mill nad an AcuRite control. He NEVER turns the crank, not even to move the table to clean chips- he cant crank as fast as AcuRite moves. For a part with one single drilled and tapped hole you might be able to move almost as fast manually, but as soon as you have even 2 holes to drill a CPNC system wins over manual hands down. Some of you at NAMES many have seen his one-off curved spoke flywheel on a miser hot-air engine. Fred, would you like to do that on your Bridgeport with cranks :-) It did take him a few minutes to do that on AcuRite. And while we are on AcuRite note that it is a 2D machine, and part of why simple jobs are faster there is because there is no motor on the Z- raising and lowering a quill to change from center drill to drill to drill to reamer is a big pain with a Z motor. That is exactly why my Grizzley mini mill will not get a z motor. Keep firmly in mind I am trying to build a CPNC machine to do a limited set of jobs, but to do them well and very simply. It is not part of the plan to eliminate any CAD/CAM systems. ron |
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Re: CPNC
Jon Elson
Ray Henry wrote:
A student at NIST recently worked out a system for CPNC that called upHey, great! When will this be released, and how about the detials, so I can convert the rest of the programs that I have in the same manner? This sounds like it will satisfy a number of users. Then, people can ask for various additions, and anyone who figures out how to code it can add the new features. Jon |
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Re: Names
Had I been at Names and heard the crowd shout down Fred over the use of
manual machining , I would have jumped up and told the hecklers to sit down and shut up. Fred is right!. There are countless times that I still use manual control of my milling machine for one off type parts and for doing a myraid of tasks like fly cutting, end milling a piece etc. Remember a few months ago there was quite a discussion on building a hand held pendant for manual control of a cnc machine for power feeding? I design CNC stuff but still use manual controls for lots of jobs. But I also know that CNC is a wonderful use of technology and is great for prodcution runs of parts. Like everything there is no one answer that is perfect for all situations. As a machinist you should select the most efficient method of producting the part. That may mean manual machine, CNC or even both. |
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Re: (calling each other) Names
Eric Keller
This (cnc vs hand cranking) is one of those subjects where we may as well
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agree to disagree and let it go. I only use cranks, but only because i didn't get trained on the CNC machine yet. I see the real machinists using CNC more than non cnc maybe because it is new, but also because it is really easy. We have the accurite system that Ron Ginger likes, and if a part has any complexity it is usually faster to punch the buttons on the machine and let the computer cut it. I know that when i am doing something boring i like to cut corners and, say take too heavy of a cut. Cnc doesn't do that. Plus if you have a bolt circle or any kind of pocket, cnc is a no-brainer. We do have 3d control. Unfortuately we have no way of transferring files to the cnc, so all programming has to be done at the machine. The good thing is that it is very easy to program and you can save your program to disk. It computes the tool path itself and is exactly what is needed around here where there is almost no production of multiple parts. If only i had 15-20k that i wouldn't notice if it was gone... eric Fred Smith wrote:I stand by my statement that the best way to machine a single |
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Re: Names
Jon Anderson
Fred Smith wrote:
I stand by my statement that the best way to machine a singleAs someone that makes his living making parts for others in qty. from 1 to several hundred, I can second this. By the time I've created geometry, run it through CAM, cleaned up the code, transferred to the computer running my MAX, proofed the program (visual run-through for errant moves), and set up the part and tool offset(s), I can often be done and on to the next part by being clever with manual setups. Pretty complex work can be done quickly without CNC, but it takes quite a base of previous experience and some cleverness to do it. I would lump home brew CNC users into three categories: #1, small commerical shops like myself, still too small and struggling to justify a commercial CNC machine, #2, folks that use CNC to supplement their limited experience with manual setups, #3, folks that just have a facination with CNC and don't really care how inefficient it is to program/setup/run a single part. Sort of the kit-plane builders of the machining world.... Of course most of us here really fit into more than one. Myself, I'm a #1 with significant traces of #3. When time is money, not relaxation, you take the fastest path, regardless of which "religion" that entials. Jon |
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Re: Names
I think the point Fred is trying to make is that CNC is not always the best
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choice. Considering the business he is in (selling CAD/CAM software) I think it is pretty honorable that he would point out that using the cranks can sometimes be a much faster may to get specific jobs done. OTOH, as you point out Jon there are jobs that can't be done as efficiently or at all with manual methods. Tim [Denver, CO] ----- Original Message -----
From: Jon Elson <jmelson@...> To: <CAD_CAM_EDM_DRO@...> Sent: Thursday, May 04, 2000 1:14 PM Subject: Re: [CAD_CAM_EDM_DRO] Re: Names
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Re: Names
Jon Elson
Fred Smith wrote:
Yes, this is probably true, but then I had a single piece (a fixtureThen we had Fred smith pushing CAD/CAM, and even making a foolishstatementthat anyone making just one or two parts shouldnt be using CNC atall.He did get soundly shouted down on that statement!For example, Drilling and Tapping a single hole. I guarantee that I plate) that needed 144 center drilled, through drilled and tapped 10-32 holes. I did the whole job in about 30 minutes, with beautiful results, with a CNC system and a tapping head. (First time I did something real with the tapping head, what a back saver!) And, I have done a number of one-off parts that couldn't be made with a manual machine, or would have taken days of fooling around with rotary tables and sine blocks. And, they would have been vastly less accurate due to having to reposition the part many times. Jon |
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Re: Conversational Programming and NAMES- very long!
Darrell,
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On my EMC install I can get up to 80 ipm or so and that is WAY beyond the instantaneous move capability of my steppers. I am running the freqmod setup on an AMD K6 500. If you are running the older steppermod or are running freqmod on a slow machine you will poop out at a slower rate, but 20 ipm seems like you have something else going on or require a very high number of steps per inch. Tim [Denver, CO] ----- Original Message -----
From: Darrell <dgehlsen@...> To: <CAD_CAM_EDM_DRO@...> Sent: Thursday, May 04, 2000 11:57 AM Subject: Re: [CAD_CAM_EDM_DRO] Conversational Programming and NAMES- very long! Jon, What you say may be true for servo but not for steppers. To make steppers work properly we need something past the Linux box to create smooth step pulses. The problem with EMC and steppers now is that the pulse train is ragged and you reach a point at about 20 IPM where the jitter on the pulse train exceeds the instantaneous move capability of the stepper motor and it stalls. Darrell |
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Re: Conversational Programming and NAMES- very long!
Jon Elson
Ray Henry wrote:
Jon wrote:Well, I'm working on a flexible interface to replace the STG card, but it could do a lot of other things, too. So, I'm planning on making a real pendant, with jog dials, override controls, etc. that would be connected to the GUI directly, rather than through the X interface. What had been holding me back was deciding how to connect the pendant to the PC. Jon |
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CPNC
Ray Henry
I'm a little late getting into this thread 'cause my eudora's not real
happy with cad_cam... I saw Ron's software at NAMES and was really impressed. I know of production machine shops that do nothing but CPNC with interfaces that are staggeringly awful by comparison. I am even more impressed with Ron's commitment to open source (GPL) the whole thing. A student at NIST recently worked out a system for CPNC that called up Jon E's programs on the screen, let the operator fill in the variables, figured the g-code and put the results into an xml delimited file. This xml file could then be saved and re-opened for editing. When the xml program was ready to run using EMC, the CP stripped out the g-code and sent it to the interpreter. Since Tcl/Tk has been suggested as the language of choice here, it has some features that are directly applicable to the CPNC system. IMO storing each "block" of a CP as a simple whitespace delimited list on each line of a single file is the way to go because it is so easy to recover the data into the appropriate variables. It would also be relatively easy to write libraries of processes that would run the same CPNC generated program using FlashCut, MaxNC, EMC, or whatever. Each machine's library would have process that are named the same but which would interpret a block for its own machine. In fact, if FlashCut proves to be obstinate about releasing the details of its language, the details of the CPNC system and it's files would still be available so that FlashCut could write a library that would run CPNC on their systems. I presume that they could then sell a protected version of that library at nominal cost. And speaking of black boxes, for that kind of money several of us would be happy to box up linux and EMC on a sbc, connect the parallel port pins to 5 amp stepper bricks and just not say it's linux. We could even call it QuickerCut. ;) Ray |
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Re: Conversational Programming and NAMES- very long!
Darrell
Jon, What you say may be true for servo but not for steppers. To make
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steppers work properly we need something past the Linux box to create smooth step pulses. The problem with EMC and steppers now is that the pulse train is ragged and you reach a point at about 20 IPM where the jitter on the pulse train exceeds the instantaneous move capability of the stepper motor and it stalls. Darrell ----- Original Message -----
From: Jon Elson <jmelson@...> To: <CAD_CAM_EDM_DRO@...> Sent: Sunday, May 03, 1998 8:52 PM Subject: Re: [CAD_CAM_EDM_DRO] Conversational Programming and NAMES- very long! discussion of shop built systems, for CAD, CAM, EDM, and DRO.
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Re: Auto Cad Lt
Jim,
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AutoCAD LT is a first rate 2 D drafting program (limited 3D). I started using AutoCAD (the real stuff) at version 2.17 (long time ago) ...... and more recently (because of job changes) ended up using AutoCAD LT (I'm up to LT 98). Learning this is very worthwhile, as it is a powerfull drafting tool, and it is easy to migrate to full AutoCAD, should the opportunity occur. If you have AutoCAD LT 97 or later, it comes with a "learning assistant" CD that would really help learn it. Hope this helps. Regards, George Potter James Cullins wrote: List |
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Re: Conversational Programming and NAMES- very long!
Ray Henry
Brian wrote
Jon wrote: [snipsnipsnip] (The only problem is that while you are insounds like a "slide hold" button is needed there! I haven't looked into the code yet but wouldn't dropping the feed override to zero in response to an external signal do this? Yes feedhold commands are available and effective during any motion caused by EMC. (manual, auto, mdi, home) The effect of feedhold is the same as pause when emc is in auto mode. The problem becomes figuring out how to make a feedhold/pause available to the operator who is "fearlessly editing" something else. For those who use the Tcl/Tk gui's, it would be possible to place a feedhold button on the bottom of all of the genedit editors and bind this to some keystroke. Ray |
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Re: CAD VS Drafting Table Re: Names
Mike Mueller
I think it depends on the part and if it for an assy or not (degree of
accuracy needed). I do drafting/designing and 3D solid modeling for living (Pro/E) and I still sketch out parts on paper once in a while at work to get the preliminary idea down or to get a real quick price quote on a part . At home I have AutoCAD but since I'm not very proficient at it anymore I find my home projects get drawn out on paper. The hand drawings don't have to be quality drawings, they just have to give you the general idea. I think by making rough sketches you can get a feel for how you will make the part and set it up. Mike Mueller |
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Re: Conversational Programming and NAMES- very long!
James Eckman
The only way I know of to get around the tendency of Windows 95+ and NT
to go to sleep is to use some form of intelligence in the controller. "Real time" NT apparently isn't. There are PC cards made by Oregon Microsystems and the like that have large command buffers and can perform lots of coordinated movements without PC intervention. They are not cheap however. Other options include DOS and RTL linux, DOS can be made to work for sure! Others in the group have had great success with Linux. The 5 minute install for EMC would make it vastly more popular with hobbiests! I'd even give it a shot... Jim |
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Re: CAD VS Drafting Table Re: Names
Wayne Bengtsson
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-----Original Message-----
From: Fred Smith [mailto:imserv@...] Sent: Thursday, 4 May 2000 9:10 PM To: CAD_CAM_EDM_DRO@... Subject: [CAD_CAM_EDM_DRO] Re: Names I don't care how smart you are, there is no getting around the fact that(rest of message CNC vs Manual Machining snipt for brevity) Seeing as this mailing list concerns CAD as well, I would like to ask the list the following: Assuming equal proficiency with a drawing board and a CAD system, is there any type of drawing that is suited to the manual process, as opposed to the CAD process? Personally, I find manual drawing a chore, so I opt for the easy way out whenever possible. Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the discussion of shop built systems, for CAD, CAM, EDM, and DRO. Addresses: Post message: CAD_CAM_EDM_DRO@... Subscribe: CAD_CAM_EDM_DRO-subscribe@... Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@... List owner: CAD_CAM_EDM_DRO-owner@..., wanliker@... Moderator: jmelson@... [Moderator] URL to this page: FAQ: bill, List Manager |
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Re: Names
Fred Smith
Then we had Fred smith pushing CAD/CAM, and even making a foolish statementFor those of you who missed the little CNC discussion forum and presentations, I was not pushing Vector at all (it was in the title, but not the words). I merely showed when it is best to use CNC as opposed to manual machining. Most of my discussion was about the $100,000 CNC lathe I watched wreck itself & a statement to be safe when using CNC machines. As far as being shouted down, this is what happens when a group of fanatical CNCers get together and one amongst them commits the blasphemy of saying that their official religion is not the only answer, especially in public. ;-) I stand by my statement that the best way to machine a single part is OFTEN and USUALLY by turning the cranks. As I pointed out in my talk, there are indeed shapes and contours that can more efficiently be machined with CNC. There are however those that are not best done that way. For example, Drilling and Tapping a single hole. I guarantee that I can do this faster on my Bridgeport than on any CNC machine. This is a quick, efficient process, all the tools are ALWAYS placed near my work area, and just reaching to push a button makes for a less efficient process. Just so any anal retentives reading this will understand, the hole is a 1/4-20, center drilled, and tap drilled with a #7 drill. The hole also has a 45 degree chamfer on each side, put there with a 45 degree countersink. The material is 1/2 aluminum. The hole location is +/- .020, it has been pre spotted with a scribe, 1/2 inch from each side of the upper left corner. Total time to make the part, including the time to decide that the hole is needed, is about 1 1/2 to 2 minutes. I don't care how smart you are, there is no getting around the fact that this is more efficiently done by cranking handles. Furthermore, If I had to put the same tapped hole in 10 identical parts, I would also say that I could still do it more efficiently without CNC. (Total time would be about 20 seconds per part 4 1/2 to 5 minutes total for ten holes.) However, I would be starting to sweat from playing material handling robot. If you use the best tool for the job, you will utilize those cranks on your lathe & mill when it makes sense to do so. You will also use CNC when it is obvious that it will yield the best results. CNC will allow you to overcome some lack of skill as a machininst, but it will not allow you to push a button and make a part. You still need to plan your process, decide on workholding techniques, set your tools, and have an understanding of the cutting processes, feeds, and speeds. Best Regards, Fred Smith IMService imserv@... Phone: 248-486-3600 or 800-386-1670 Fax:248-486-3698 |
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A box for CPNC
John Guenther
Ron,
Take a look at www.simplestep.com for their serial interface intelligent controllers. They come in single, dual and three axis versions and use serial interface to the host PC I thinks you could use these in place of the Flashcut controller and accomplish the same thing. John Guenther |
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Re: CAD VS Drafting Table Re: Names
I think that drawing by hand is great for quick sketches, and in my case
sending our preliminary drawings for price quotes, but there's just no comparison to using CAD. This is especially true when manufacturing from drawings, you don't need to remember all of those formulas you learned in math class...just click the mouse a few times! Jeff |
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Re: CAD VS Drafting Table Re: Names
My wife, who was dragged kicking and screaming from paper to CAD (space
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planning / architect) still maintains that paper is faster for preliminary drawings, sketches etc. while one works out a design, then CAD becomes faster doing "real" drawings. I also have difficulty drawing by hand (an understatement) & once I got AutoCAD (about 15 years ago) found that drafting wasn't a chore anymore ...... I could concentrate on what was being drawn, rather than the problem getting lines straight, not smudging the drawing etc. (being left handed never helped). However, after using CAD for so long, I find that I can now make drawings by hand much easier than before I began CAD, as I have gotten much better at "visualizing" my drawing .... knowing what it should look like, before it gets into the computer or on paper. Regards, George Potter Placerville, California Wayne Bengtsson wrote: Assuming equal proficiency with a drawing board and a CAD system, is there |
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