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- CAD-CAM-EDM-DRO
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Re: Increasing DRO resolution
mayfieldtm
Paul:
There are "Interpolator" units available that can increase the resolution of encoders and linear scales. These are electronic and usually available in 2,5 and 10 times the encoder resolution. The catch is that the quadrature signal output of your encoder must be a sine wave, not a digital output. Most encoders use one or the other and sometimes both. The sine wave output can come in a verity of levels, so the interpolator must match. Of course the quality of your encoder and mechanical connection must be appropriate. One more note: The Output of most of the Interpolators is digital. So your DRO must accept this. I have seen 10x setups that were quite accurate. Tom M. |
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Re: Motor Brackets
John Guenther
Hi Marv,
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I too would like to see the drawing. I can read acad R14 also. John Guenther Sterling, Virginia -----Original Message----- |
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Re: Motor Brackets
Hi Marv,
I'm not Phil but, if you don't mind, I would like to see your DWG. I am currently running a Sherline mill, but am building a data base for the next bigger and better if you know what I mean :-) Thanx, al P.S. I can read acad R14. al --- In CAD_CAM_EDM_DRO@y..., Marv Frankel <dcdziner@p...> wrote: Phil,but direct drive, at www.matronics.com/cnc2/ . I also have an AutoCaddrawing that someone posted on the net, of a geared down motor mount usingtiming belts. If you can read an Acad R14 DWG file, I'll be glad to emailit to you, or tell me what format you'd like, and I'll send it to you. Ithink the guy who designed this gearbox also has some pictures posted, but Idon't remember where. |
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Re: Motor Brackets
Marv Frankel
Phil,
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You can see pictures of motor brackets, not with timing belts, but direct drive, at www.matronics.com/cnc2/ . I also have an AutoCad drawing that someone posted on the net, of a geared down motor mount using timing belts. If you can read an Acad R14 DWG file, I'll be glad to email it to you, or tell me what format you'd like, and I'll send it to you. I think the guy who designed this gearbox also has some pictures posted, but I don't remember where. Marv Frankel Los Angeles ----- Original Message -----
From: "Phil Whittingham" <philw3@...> To: <CAD_CAM_EDM_DRO@...> Sent: Sunday, October 20, 2002 3:15 PM Subject: [CAD_CAM_EDM_DRO] Motor Brackets I'm starting to look at designing motor brackets for my mill conversionaol://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........
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Re: Resolvers vs Encoders
Marcus & Eva wrote:
Hi All:Resolvers use varying magnetic coupling to provide signals which vary in amplitude (and have a sign, ie. + or - phase relationship). A sine wave excitation is applied to one winding, and sine waves are produced on 2 other windings, which vary in amplitude as the resolver is rotated. Interpolation is used to obtain higher resolution information than the raw quadrature cycles inherent in the output. Most encoders today are optical, with LED light sources. back in the days before LEDs, encoders were considered unreliable, because the light bulbs would burn out. Most encoders in modest systems, especially home CNC systems, are used at their inherent resolution, and not interpolated. What is the implication for machine performance?Not much. but, a device to read out position from a resolver is more expensive, maybe MUCH more expensive, than what is needed to read position from an encoder Is a retrofit from resolvers to encoders a worthwhile effort?I did it on my machine. So, yes, I'd consider it worthwhile. When did resolvers go out of favour and why?I don't know if they are "out of style", as some large machine builders still use them. I'm casting amorously about, for small CNC turning centers, and I've heardCertainly. Don't let a resolver-equipped machine scare you off. It will probably be cheaper to retrofit with encoders as part of the CNC controller retrofit. It is possible that there are black-box resolver converters in the CNC machine that can be used with the new controller, though. If so, then you would not need to pull the resolvers. Jon |
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Re: .0055 of play in the z-axis
jbordens wrote:
well after 3 months, i finally have my machine. Overall, i'm prettyNo proper CNC system uses a coarse rack and pinion on the quill. Backlash is not the only concern. Many spur gear profiles do not provide linear movement precisely proportional to rotary input. Depending on how the gear was cut, there may be cyclical errors in the gear teeth as well. I would recommend using a screw of some type, and providing a very stiff linkage between the nut and the quill. Jon |
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Re: Increasing DRO resolution
paul_norton2001 wrote:
This has probably been dealt with before but I can't find it in the archive.I think this applies more to CNC motion control systems rather than DROs. Jon |
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Re: Motor Brackets
djld98370
I assume your talking woodruff keys .... just lay a pair of wire
cutter jaws parallel to the shaft and squeeze down on the end of the key and push down on the handles ,,,, I would not suggest useing a hammer on the screw,,, the sand on the inside of the castings or the Bondo on the out side well fall out. Duffy -- In CAD_CAM_EDM_DRO@y..., Phil Whittingham <philw3@c...> wrote: John,overkill for such a simple issue. Know I know this is a legitimate approachI may try that.Taig xx.the timingdials and end caps off the shafts. reach itbelts and pulleys ? if you have trouble.there, 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: Motor Brackets
John,
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I thought about the tap and drill approach but this seemed like overkill for such a simple issue. Know I know this is a legitimate approach I may try that. I'll check out the photos. I like the sound of the off the shelf approach! Thanks Phil -----Original Message-----
From: stevenson_engineers [mailto:machines@...] Sent: Sunday, October 20, 2002 7:14 PM To: CAD_CAM_EDM_DRO@... Subject: [CAD_CAM_EDM_DRO] Re: Motor Brackets --- In CAD_CAM_EDM_DRO@y..., Phil Whittingham <philw3@c...> wrote:Two ways to remove keys Phil. One is to tap on the end with a sharp chisel to force the key up and the other is to drill and tap it and insert a jack screw to extract it. Not knowing what type of mill you have you can have a look in the photos section on the web site at some files near the end marked Taig xx. This is the design I chose to use to reduce overhang and cheap off the shelf drive components. John S. I'm starting to look at designing motor brackets for my millconversion but have an issue.luck. Is there a trick to this ? I've tried tapping it with a hammer butno luck. Addresses: FAQ: FILES: OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. I consider this as 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........ Post messages: 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@... timg@... [Moderator] URL to this group: bill, List Mom List Owner Your use of Yahoo! Groups is subject to |
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Re: Resolvers vs Encoders
This is all correct. Another way to look at it is two coils which change
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their angle to one another. The resolver is sent a sine wave. The signal goes through the coils and comes back with some phase change. The phase change is proportional to the angle between the two coils. The resolver board sends out a sine wave then it reads the difference in phase between what it sent and what was returned, this provides absolute angle on the resolver shaft. With a high frequency carrier wave, a resolver is immune to external electrical fields. This allows the resolver to be as much as 600 feet from the decoding circuits. 15 years ago the support circuits for incremental encoders were pretty poor. The alternative was an absolute encoder. Those required large glass wheels in order to get high resolution for angle. In addition, encoders require the decoding electronics near to the sensor, normally inside the encoder body itself. Since the electronics were subject to environmental conditions, it was quite difficult to put an encoder on the back end of a motor which might get to 190 degrees F or more. A resolver is pretty much solid state, just a couple coils, and could be put into very difficult situations such as steel mills and other hot nasty places. I have used resolvers in many situations. The company I worked for had an old fashion preference for them. The resolver support boards were certainly expensive, but that was only because we had a high margin on them. The chip that does all the work is from Analog Devices and is really not too expensive. The only excuse for switching to resolvers is if you have a technical issue with encoders that cannot be overcome by conventional practices. This is pretty uncommon these days. GTJ -----Original Message-----
From: w.higdon@... [mailto:w.higdon@...] Sent: Sunday, October 20, 2002 4:40 PM To: CAD_CAM_EDM_DRO@... Subject: Re: [CAD_CAM_EDM_DRO] Resolvers vs Encoders I'll try, altough Jon, could probaly do better. A resolver can be a transformer with a 2 or more phase primary. The secondary is inside the primary and is free to move, some are linear, and some are rotary. The Rotary ones usually use sliprings so the secondary can rotate through a full circle (360). Being a analog device the need something to convert them to digital. The chips are rather expensive now, when I worked at Entec, a new board cost between $500 to $1000 depending on accuracy. a encoder can either be a "Absolute encoder" (works just like a synchro with conversion built in). These are usually VERY expensive and limited in resloution. The second kind are "Incremental encoders" these output a series of pulses as they are moved. If they put out a pair of pulses streams with a phase difference between the pulse streams can be used to determine the direction of movement. Now that this is as clear as mud, I'll let Jon or someoone else clarify it. Bill Higdon PS you can convert a syncro machine to a eincremental encoder machine, by replacing the syncro's with suitable encoders. I did one upgrade (conversion)like that while at Entec. Hi All:than building from scratch or retrofitting a manual machine...especially whenyou consider that the enclosures, the coolant pumps, the ballscrews, the wayif 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........Addresses: FAQ: FILES: OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. I consider this as 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........ Post messages: 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@... timg@... [Moderator] URL to this group: bill, List Mom List Owner Your use of Yahoo! Groups is subject to |
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Re: Motor Brackets
stevenson_engineers
--- In CAD_CAM_EDM_DRO@y..., Phil Whittingham <philw3@c...> wrote:Two ways to remove keys Phil. One is to tap on the end with a sharp chisel to force the key up and the other is to drill and tap it and insert a jack screw to extract it. Not knowing what type of mill you have you can have a look in the photos section on the web site at some files near the end marked Taig xx. This is the design I chose to use to reduce overhang and cheap off the shelf drive components. John S. I'm starting to look at designing motor brackets for my millconversion but have an issue.luck. Is there a trick to this ? I've tried tapping it with a hammer butno luck. |
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Motor Brackets
I'm starting to look at designing motor brackets for my mill conversion
but have an issue. I'm trying to remove the key from the x and y screws but having no luck. Is there a trick to this ? I've tried tapping it with a hammer but no luck. It looks as though I need to remove this key before I can slide the dials and end caps off the shafts. Has anyone got pictures/designs for motor brackets when using timing belts and pulleys ? thanks Phil |
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Re: Resolvers vs Encoders
I'll try, altough Jon, could probaly do better.
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A resolver can be a transformer with a 2 or more phase primary. The secondary is inside the primary and is free to move, some are linear, and some are rotary. The Rotary ones usually use sliprings so the secondary can rotate through a full circle (360). Being a analog device the need something to convert them to digital. The chips are rather expensive now, when I worked at Entec, a new board cost between $500 to $1000 depending on accuracy. a encoder can either be a "Absolute encoder" (works just like a synchro with conversion built in). These are usually VERY expensive and limited in resloution. The second kind are "Incremental encoders" these output a series of pulses as they are moved. If they put out a pair of pulses streams with a phase difference between the pulse streams can be used to determine the direction of movement. Now that this is as clear as mud, I'll let Jon or someoone else clarify it. Bill Higdon PS you can convert a syncro machine to a eincremental encoder machine, by replacing the syncro's with suitable encoders. I did one upgrade (conversion)like that while at Entec. Hi All: |
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Re: polymer concrete
William Scalione
Hi, well i am no expert but the machine i saw being built they poured thea base of Urethane, stone powder and some type of emulsion binder to keepthe viscosity even till it was set-up. The small piece i had didnt bounce whenthey use. cul brian f.Brian, Was the machine base basicly a hollow form made of steel, or cast iron? What I'm trying to figure out is, if it would be possible to build a small machine base out of 1/2" thick aluminum or steel plate, bolt it together, and then have it machined to be square and true. Once everything is done, fill it full of the polymer concrete, and bolt THK style rails to the frame. Seems like if this could be done, we could come up with a design for the group and have a bunch of the frame parts made and sold as a kit. Looks like it would make a nice machine, Desktop size, maybe 8 X 12 working envelope. It would look like this No idea what it would cost to have something like that done Bill |
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Vector Macro Toolbar available
IMService
For those using or testing VectorCad and/or VectorCam, we have nearly completed our new Macro Tool Bar. This is a floating toolbar program that enables creation of keyboard macro scripts that interact with Vector Cad, VectorCam and Notepad. The program does not require that you learn a programming language like Visual Basic or C, and is available at no charge from our user forum. It incorporates simple loops, input requests, numeric and string variables and can automate multiple repetitive key stroke tasks to a simple button click.
Best Regards, Fred Smith- IMService Listserve Special discounts and offers are at: We are THE source for low cost Cad Cam |
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Re: newbie questions on visual mill
Peter
Hi Steve,
I'm assuming you have VM 4.0? I'm still running 3.2 while my upgrade ships. Answers below: Steve Ross wrote: HelloYes, probably. In VM 3.2 I have "Create Machine Ops", Create Menu" and "Create Regions" - all have a help screen behind them. Email Mecsoft with the problem. (If you ask which create page you are looking for help, I send you a screen capture of that part of my help. Yes, in VM3.2 it is under "Edit/Transform Selection" Just select the Scale tab. You may have to "select" the work first, before scaling. ( I see there is also an input for metric/imperial units - however I have always set mm via the "Preferences" menu. Once set, it stays in mm.) See above. You'll have to play with the post editor and look at the produced G-Code files to get a clear understanding of how things work, but you can perform multiple machining operations with the same tool - if you want. I have a BP clone without a toolchanger and my Flashcut controller just sends the table to my specified tool change position (just an XYZ coordinate) I've pasted a sample tool change below to give you an idea how I configured the post processor: ... N379X-3.749Y-12.727 N380Z3. N381Z10.167F800 (OPERATION: Horizontal Finishing) N382G21 N383M05 M09 (Motor & Coolant off before rapid) N384G28 (Rapid move to Tool Change Position) N385T23M06 N386G43 H23 (Apply Cutter Compensation) N387G29 X-3.749Y-12.727Z10.167 (Re-position Tool) N388S4000M3M7 (Set RPM's, Motor On and Mist Coolant On) N389G0X-62.325Y-15.204Z6.794 N390G1Z2.475F800 N391Z1.875F250 N392Y-13.877 N393X-62.317Y-13.445 ... If you're not familiar with tool changing - make sure you cut air the first few times to understand how tool length comp works. (You need to measure the length of all your tools from a datum - G43 just takse the difference between tool lengths and applies an offset.) What controller are you using with your Taig? Someone in the group may be familiar with how the Tiag controller handles tool changes. Have fun and ask away as you learn! Cheers, Peter |
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Re: newbie questions on visual mill
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-----Original Message-----If I select "Create Menu" in the help I get the same error. Interestingly they mention a create toolbar in the tutorials that I can not seem to find also. All the functions are on the Curve menu so it is possibly they just renamed the function. Would like to find the toolbar as it would be handy. 2. Can you resize your cad project bigger or smaller for postNot sure and I would do it in my CAD program, but in the Post Processor editor there is boxes for scaling factors on the Motion tab. There may be other ways I just have not seen because I have not looked. 3. How can I switch over to millimeters from inchs or is thatPreference menu and then Part Units. 4. how does the different operations i.e roughing, finishingDepends upon the post that you use. You can post each operation by itself and then do each one as a separate process. You can also change the tool changer code that is output to do a pause instead (or anything else your controller is capable of). It is all configured in the post processor generator (standard Visual Mill only, not on basic they say). So far I have taken the Flashcut post and hacked it to be more EMC friendly. Was pretty quick and easy. I started with the Flashcut because the output seemed pretty plain vanilla and I wanted very basic to begin with. Didn't want to deal with offsets and such until I have a better feel for the whole process. Tim [Denver, CO] www.KTMarketing.com/CNC.html |
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Re: Resolvers vs Encoders
Marcus & Eva
Hi All:
Can any of you explain to me, the differences between resolvers and encoders. What is the implication for machine performance? Is a retrofit from resolvers to encoders a worthwhile effort? When did resolvers go out of favour and why? I'm casting amorously about, for small CNC turning centers, and I've heard the terms mentioned, especially in regard to Hardinge machines. Mid eighties machines seem to be the transition point from the resolver system to the encoder system. It looks to me like there is a fair amount of very nice old CNC iron from that era out there available for very little money...certainly far less than building from scratch or retrofitting a manual machine...especially when you consider that the enclosures, the coolant pumps, the ballscrews, the way covers etc, etc are all already there. Cheers Marcus |
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