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I am just about done with my Must Do's and will be headed to my shop for the next two or three months.
I want to do ELS (#RELS) on my Craftsman?101.07403 12x36 Lathe. I also have a Mini Lathe 4x12 which
I will do later.
I would like to document the full story possible for publication or at least a detailed web post.
Thought I'd start with the encoder.
Where do I start? What encoder do I want? I googled rotary encoders and my head is spinning.?
Especially the price I can pay $16.00 - $30.00 or $300-$600.00, even with the same brand name
there can be $200.00+ difference from different suppliers.
I will be mounting the encoder on the spindle at a 1:1 drive so a 2 - 3000 rpm encoder should work.
I appreciate the help and would really like to document this selection.
Ralph
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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Hi, Ralph, The existing RELS Arduino sketch is set up for 1800 pulses per spindle rotation, though that can be changed.? Have you thought about how you will affix the encoder to the spindle?? It might be more convenient, and easier to find a low-cost encoder, if you can increase the encoder speed and use a lower pulse per rev encoder.? John and I both (because I basically duplicated his implementation) used 600 PPR, belt driven with a timing belt at a 3:1 ratio, resulting in 3 encoder revolutions per spindle rev and 1800 pulses per spindle rev. There are several factors you have to consider.? (BTW, I spent 33 years working for a company that manufactures encoders. Besides working on applications, I also sometimes wrote specs for how they were supposed to perform.)? The most critical ones here are: RPM - All encoders have a maximum mechanical rotation rate. If the maximum spindle speed is 2500 RPM, and you are driving 1:1, then your encoder must have an RPM rating higher than that.? If driving 2:1 in the same example, the encoder will be running 5000 RPM at a 2500 RPM spindle speed. Output Frequency - The pulses are sent out of the encoder via a digital system, and this system has a maximum frequency.? Say that your encoder is 600 PPR and is turning at 2500 RPM. 600 P/R X 2500 R/M X 1/60 M/sec = 25,000 pulses/sec Or, 25 kHz.? So you need to decide on PPR, and gear or belt ratio between spindle and encoder, before you can calculate the maximum frequency rating you need. Radial Bearing Load - The bearings in an encoder are only rated for a certain number of rotations.? This number decreases rapidly with radial bearing load. There is also a maximum radial load the bearing can take at all. In large, industrial systems, this is carefully calculated, but in our application, just use the lowest load you can. In my photos below, I used the weakest springs that I could while still keeping the belt fully engaged.? BTW, don't be fooled into thinking that a flexible coupling eliminates this problem.? They only work correctly within a very small specified range.? Outside that range, they apply substantial loads to the encoder shaft. Below is a photo of my encoder installation, "borrowed", as I have said, from John Lindo's design.? I hope this helps...  -- Regards, Charlie New Jersey, USA MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.
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The original RELS software was based upon using an 1800 line encoder
disk taken from an HP printer, therefore No Cost!
That option is still available to you if you can get hold of a disk,
read head, mount and drive it in some way and add some electronics.
If you do not want to go that way then as you say purchase an encoder.
You do not need an "Index" output just an A and B signal. The original
software was written around 1800 line per spindle revolution however it
is possible to use a different number of lines but pick something
somewhere close to this sort of value.
I would assume that you will be belt driving the encoder so there is
really no need to stay at 1:1.
The final specification for the encoder therefore resolves to :-
5v supply, A and B signals, index not required, around 1800 lines per
rev after belt ratio, capable of the maximum spindle speed after belt ratio.
Do not get sidetracked by Quadrature counts if quoted, you are only
interested in the number of lines.
On my system I have a 600 line encoder running at 3:1 and it cost me
maybe ?15 from China.
If you need any further information just yell
Richard Edwards
toggle quoted message
Show quoted text
On 09/12/2019 15:55, Ralph Hulslander wrote: I am just about done with my Must Do's and will be headed to my shop
for the next two or three months.
I want to do ELS (#RELS) on my Craftsman?101.07403 12x36 Lathe. I also
have a Mini Lathe 4x12 which
I will do later.
I would like to document the full story possible for publication or at
least a detailed web post.
Thought I'd start with the encoder.
Where do I start? What encoder do I want? I googled rotary encoders
and my head is spinning.
Especially the price I can pay $16.00 - $30.00 or $300-$600.00, even
with the same brand name
there can be $200.00+ difference from different suppliers.
I will be mounting the encoder on the spindle at a 1:1 drive so a 2 -
3000 rpm encoder should work.
I appreciate the help and would really like to document this selection.
Ralph
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill
press, 40 watt laser, Consew brushless DC motors and a non working 3D
printer
|
On Dec 9, 2019, at 11:46 AM, Richard < edelec@...> wrote:
That option is still available to you if you can get hold of a disk,
read head, mount and drive it in some way and add some electronics.
Note these are readily available for free, by picking up dead inkjet printers. The encoder needed is on the left-hand end of the platen and the sensor circuit is usually a simple U-shaped board attached to another circuit on there. I have several of these at home; if I can remember, I¡¯ll post a pic later. There are a number of online projects recycling these parts
printers are also useful sources for nylon gears, a variety of springs, small DC motors and steel rods of different diameters (mostly like 5-8 mm or so) Old laser jet printers also have a wealth of motors and mechanical parts, but they¡¯re harder to find. I've scavenged a half-dozen inkjets simply by picking them up out of the tip.
The scanners on the multi-function ones also provide a very nice 8x12 or so piece of optically flat glass; quite useful for things like a base for a tool sharpening setup.
--? Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
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Actually I will be using 1:1 I have a 32t gear to match the 32t gear on the end of my spindle:
I will have to come up with a shaft but gee isn't that why we have a lathe? Also a mounting bracket I have some 3x4 aluminium angle and some plate steel also a vertical?mill and a welder and drill press so I should be able to come up with something. I can even use the indexed pivot to engage the encoder.
Ralph
On Dec 9, 2019, at 11:46 AM, Richard < edelec@...> wrote:
That option is still available to you if you can get hold of a disk,
read head, mount and drive it in some way and add some electronics.
Note these are readily available for free, by picking up dead inkjet printers. The encoder needed is on the left-hand end of the platen and the sensor circuit is usually a simple U-shaped board attached to another circuit on there. I have several of these at home; if I can remember, I¡¯ll post a pic later. There are a number of online projects recycling these parts
printers are also useful sources for nylon gears, a variety of springs, small DC motors and steel rods of different diameters (mostly like 5-8 mm or so) Old laser jet printers also have a wealth of motors and mechanical parts, but they¡¯re harder to find. I've scavenged a half-dozen inkjets simply by picking them up out of the tip.
The scanners on the multi-function ones also provide a very nice 8x12 or so piece of optically flat glass; quite useful for things like a base for a tool sharpening setup.
--? Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
There is no way I would run an encoder for the ELS via a gear. I would
suggest that with an encoder with a shaft you only consider a timing
belt drive.
Also why would you want to disengage the encoder?
Richard
toggle quoted message
Show quoted text
On 09/12/2019 21:26, Ralph Hulslander wrote: Actually I will be using 1:1 I have a 32t gear to match the 32t gear
on the end of my spindle:
IMG_20191209_153625804.jpg
I will have to come up with a shaft but gee isn't that why we have a
lathe?
Also a mounting bracket I have some 3x4 aluminium angle and some plate
steel
also a vertical?mill and a welder and drill press so I should be able
to come up with something. I can even use the indexed pivot to engage
the encoder.
Ralph
On Mon, Dec 9, 2019 at 2:13 PM Bruce J <bruce.desertrat@...
<mailto:bruce.desertrat@...>> wrote:
On Dec 9, 2019, at 11:46 AM, Richard <edelec@...
<mailto:edelec@...>> wrote:
That option is still available to you if you can get hold of a disk,
read head, mount and drive it in some way and add some electronics. Note these are readily available for free, by picking up dead
inkjet printers. The encoder needed is on the left-hand end of the
platen and the sensor circuit is usually a simple U-shaped board
attached to another circuit on there. I have several of these at
home; if I can remember, I¡¯ll post a pic later. There are a number
of online projects recycling these parts
printers are also useful sources for nylon gears, a variety of
springs, small DC motors and steel rods of different diameters
(mostly like 5-8 mm or so) Old laser jet printers also have a
wealth of motors and mechanical parts, but they¡¯re harder to find.
I've scavenged a half-dozen inkjets simply by picking them up out
of the tip.
The scanners on the multi-function ones also provide a very nice
8x12 or so piece of optically flat glass; quite useful for things
like a base for a tool sharpening setup.
--
Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill
press, 40 watt laser, Consew brushless DC motors and a non working 3D
printer
|
Just saying I could disengage, who knows why. I could put a flat belt on the two gears, if you really want a timing belt.
I am really looking for feedback and help since I do not know what I am doing (I have never done this) but I need the whys.
Ralph
On Mon, Dec 9, 2019 at 6:42 PM Richard < edelec@...> wrote: There is no way I would run an encoder for the ELS via a gear. I would
suggest that with an encoder with a shaft you only consider a timing
belt drive.
Also why would you want to disengage the encoder?
Richard
On 09/12/2019 21:26, Ralph Hulslander wrote:
> Actually I will be using 1:1 I have a 32t gear to match the 32t gear
> on the end of my spindle:
> IMG_20191209_153625804.jpg
>
> I will have to come up with a shaft but gee isn't that why we have a
> lathe?
> Also a mounting bracket I have some 3x4 aluminium angle and some plate
> steel
> also a vertical?mill and a welder and drill press so I should be able
> to come up with something. I can even use the indexed pivot to engage
> the encoder.
>
> Ralph
>
> On Mon, Dec 9, 2019 at 2:13 PM Bruce J <bruce.desertrat@...
> <mailto:bruce.desertrat@...>> wrote:
>
>
>
>>? ? ?On Dec 9, 2019, at 11:46 AM, Richard <edelec@...
>>? ? ?<mailto:edelec@...>> wrote:
>>
>>? ? ?That option is still available to you if you can get hold of a disk,
>>? ? ?read head, mount and drive it in some way and add some electronics.
>
>? ? ?Note these are readily available for free, by picking up dead
>? ? ?inkjet printers. The encoder needed is on the left-hand end of the
>? ? ?platen and the sensor circuit is usually a simple U-shaped board
>? ? ?attached to another circuit on there. I have several of these at
>? ? ?home; if I can remember, I¡¯ll post a pic later. There are a number
>? ? ?of online projects recycling these parts
>
>? ? ?printers are also useful sources for nylon gears, a variety of
>? ? ?springs, small DC motors and steel rods of different diameters
>? ? ?(mostly like 5-8 mm or so) Old laser jet printers also have a
>? ? ?wealth of motors and mechanical parts, but they¡¯re harder to find.
>? ? ?I've scavenged a half-dozen inkjets simply by picking them up out
>? ? ?of the tip.
>
>? ? ?The scanners on the multi-function ones also provide a very nice
>? ? ?8x12 or so piece of optically flat glass; quite useful for things
>? ? ?like a base for a tool sharpening setup.
>
>? ? ?--
>? ? ?Bruce Johnson
>
>? ? ?"Wherever you go, there you are." B. Banzai, PhD
>
>
> --
> Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill
> press, 40 watt laser, Consew brushless DC motors and a non working 3D
> printer
>
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
On Mon, Dec 9, 2019 at 06:42 PM, Richard wrote:
There is no way I would run an encoder for the ELS via a gear. I would
suggest that with an encoder with a shaft you only consider a timing
belt drive.
Ralph, I agree with Richard.? The bearing on a small, inexpensive encoder of the type we can source easily from China would simply not support the radial load of a gear that size.? (Personally, I would not drive it with any sized gear, but that's me.)? Timing belt drive would really be the preferred approach, IMO. The company I worked for made very heavy-duty encoders that would handle a gear like that (price: around US $600.00 each and up), but we would STILL recommend that a separate shafted bearing assembly was used with the gear, and the encoder coupled to the end of that shaft, thereby minimizing loading.? Another alternative, of course, would be a hollow-shaft encoder, but again, not very price friendly when big enough for our spindles.? You might be able to find a not terribly expensive one from China; I have never searched. -- Regards, Charlie New Jersey, USA MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.
|
Gears have way more "slop" than the steps on your encoder. If the gear rattles a bit, your encoder could go crazy trying to discern speed and direction.
Just saying I could disengage, who knows why. I could put a flat belt on the two gears, if you really want a timing belt.
I am really looking for feedback and help since I do not know what I am doing (I have never done this) but I need the whys.
Ralph
On Mon, Dec 9, 2019 at 6:42 PM Richard < edelec@...> wrote: There is no way I would run an encoder for the ELS via a gear. I would
suggest that with an encoder with a shaft you only consider a timing
belt drive.
Also why would you want to disengage the encoder?
Richard
On 09/12/2019 21:26, Ralph Hulslander wrote:
> Actually I will be using 1:1 I have a 32t gear to match the 32t gear
> on the end of my spindle:
> IMG_20191209_153625804.jpg
>
> I will have to come up with a shaft but gee isn't that why we have a
> lathe?
> Also a mounting bracket I have some 3x4 aluminium angle and some plate
> steel
> also a vertical?mill and a welder and drill press so I should be able
> to come up with something. I can even use the indexed pivot to engage
> the encoder.
>
> Ralph
>
> On Mon, Dec 9, 2019 at 2:13 PM Bruce J <bruce.desertrat@...
> <mailto:bruce.desertrat@...>> wrote:
>
>
>
>>? ? ?On Dec 9, 2019, at 11:46 AM, Richard <edelec@...
>>? ? ?<mailto:edelec@...>> wrote:
>>
>>? ? ?That option is still available to you if you can get hold of a disk,
>>? ? ?read head, mount and drive it in some way and add some electronics.
>
>? ? ?Note these are readily available for free, by picking up dead
>? ? ?inkjet printers. The encoder needed is on the left-hand end of the
>? ? ?platen and the sensor circuit is usually a simple U-shaped board
>? ? ?attached to another circuit on there. I have several of these at
>? ? ?home; if I can remember, I¡¯ll post a pic later. There are a number
>? ? ?of online projects recycling these parts
>
>? ? ?printers are also useful sources for nylon gears, a variety of
>? ? ?springs, small DC motors and steel rods of different diameters
>? ? ?(mostly like 5-8 mm or so) Old laser jet printers also have a
>? ? ?wealth of motors and mechanical parts, but they¡¯re harder to find.
>? ? ?I've scavenged a half-dozen inkjets simply by picking them up out
>? ? ?of the tip.
>
>? ? ?The scanners on the multi-function ones also provide a very nice
>? ? ?8x12 or so piece of optically flat glass; quite useful for things
>? ? ?like a base for a tool sharpening setup.
>
>? ? ?--
>? ? ?Bruce Johnson
>
>? ? ?"Wherever you go, there you are." B. Banzai, PhD
>
>
> --
> Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill
> press, 40 watt laser, Consew brushless DC motors and a non working 3D
> printer
>
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Just for info here are some (poor) photos of the encoder and stepper
mount on my lathe. Just remove that 32 tooth gear and replace with a pulley.
Note that I mounted the stepper on the banjo and drive through the
original gear box which allows drive to the sliding feed or lead-screw.
Ralph, on your lathe I would initially remove all of the bits associated
with the change wheels then assess how you will handle the X mechanics,
maybe by refitting some items.
Richard
toggle quoted message
Show quoted text
On 09/12/2019 21:26, Ralph Hulslander wrote: Actually I will be using 1:1 I have a 32t gear to match the 32t gear
on the end of my spindle:
IMG_20191209_153625804.jpg
I will have to come up with a shaft but gee isn't that why we have a
lathe?
Also a mounting bracket I have some 3x4 aluminium angle and some plate
steel
also a vertical?mill and a welder and drill press so I should be able
to come up with something. I can even use the indexed pivot to engage
the encoder.
Ralph
On Mon, Dec 9, 2019 at 2:13 PM Bruce J <bruce.desertrat@...
<mailto:bruce.desertrat@...>> wrote:
On Dec 9, 2019, at 11:46 AM, Richard <edelec@...
<mailto:edelec@...>> wrote:
That option is still available to you if you can get hold of a disk,
read head, mount and drive it in some way and add some electronics. Note these are readily available for free, by picking up dead
inkjet printers. The encoder needed is on the left-hand end of the
platen and the sensor circuit is usually a simple U-shaped board
attached to another circuit on there. I have several of these at
home; if I can remember, I¡¯ll post a pic later. There are a number
of online projects recycling these parts
printers are also useful sources for nylon gears, a variety of
springs, small DC motors and steel rods of different diameters
(mostly like 5-8 mm or so) Old laser jet printers also have a
wealth of motors and mechanical parts, but they¡¯re harder to find.
I've scavenged a half-dozen inkjets simply by picking them up out
of the tip.
The scanners on the multi-function ones also provide a very nice
8x12 or so piece of optically flat glass; quite useful for things
like a base for a tool sharpening setup.
--
Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill
press, 40 watt laser, Consew brushless DC motors and a non working 3D
printer
|
When I converted my South Bend Heavy 10L I wanted to maintain the historical (1942) operation of the lathe.?? I wanted to keep the gear cover.? I can post some pictures of failed attempts.? Ultimately I went this route with one hall sensor detecting a magnet embedded into the spindle clamp bolt hole.? A small bracket held the plastic tube. ? 
? The sensor fits into the tube with the backside at right angles. 
? The sensor is epoxied in place. 
? That's the extent of the electrical work for spindle sensing. ? The mechanical side of the lead screw drive is at the other end.? I bought a surplus lead screw mount and machined away a bit to make room for the shaft extension.? The 2:1 reduction provides enough torque/speed with the 280 oz-in motor driven with 8 micro-steps/step from my ELS. ? At the gear box end the appropriate leavers are placed into neutral or not engaged.? The lathe now runs very quietly and the loudest noise comes from the stepper motor.? I plan on mounting the Bergerda AC servo with probably 3:1 for a dramatic increase in spead and better torque. ? 
? And if I want full CNC I can add a motor to the cross slide and then run MACH3 which can also do CNC with a single pulse per rev. John Dammeyer ? ?
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Show quoted text
> -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Richard > Sent: December-10-19 1:30 AM > To: [email protected] > Subject: Re: [digitalhobbyist] Step #1 Encoder > > Just for info here are some (poor) photos of the encoder and stepper > mount on my lathe. Just remove that 32 tooth gear and replace with a pulley. > Note that I mounted the stepper on the banjo and drive through the > original gear box which allows drive to the sliding feed or lead-screw. > Ralph, on your lathe I would initially remove all of the bits associated > with the change wheels then assess how you will handle the X mechanics, > maybe by refitting some items. > Richard > > On 09/12/2019 21:26, Ralph Hulslander wrote: > > Actually I will be using 1:1 I have a 32t gear to match the 32t gear > > on the end of my spindle: > > IMG_20191209_153625804.jpg > > > > I will have to come up with a shaft but gee isn't that why we have a > > lathe? > > Also a mounting bracket I have some 3x4 aluminium angle and some plate > > steel > > also a vertical?mill and a welder and drill press so I should be able > > to come up with something. I can even use the indexed pivot to engage > > the encoder. > > > > Ralph > > > > On Mon, Dec 9, 2019 at 2:13 PM Bruce J <bruce.desertrat@... > > <mailto:bruce.desertrat@...>> wrote: > > > > > > > >>???? On Dec 9, 2019, at 11:46 AM, Richard <edelec@... > >>???? <mailto:edelec@...>> wrote: > >> > >>???? That option is still available to you if you can get hold of a disk, > >>???? read head, mount and drive it in some way and add some electronics. > > > >???? Note these are readily available for free, by picking up dead > >???? inkjet printers. The encoder needed is on the left-hand end of the > >???? platen and the sensor circuit is usually a simple U-shaped board > >???? attached to another circuit on there. I have several of these at > >???? home; if I can remember, I?ll post a pic later. There are a number > >???? of online projects recycling these parts > > > >???? printers are also useful sources for nylon gears, a variety of > >???? springs, small DC motors and steel rods of different diameters > >???? (mostly like 5-8 mm or so) Old laser jet printers also have a > >???? wealth of motors and mechanical parts, but they?re harder to find. > >???? I've scavenged a half-dozen inkjets simply by picking them up out > >???? of the tip. > > > >???? The scanners on the multi-function ones also provide a very nice > >???? 8x12 or so piece of optically flat glass; quite useful for things > >???? like a base for a tool sharpening setup. > > > >???? -- > >???? Bruce Johnson > > > >???? "Wherever you go, there you are." B. Banzai, PhD > > > > > > -- > > Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill > > press, 40 watt laser, Consew brushless DC motors and a non working 3D > > printer > > > > > ?
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I follow a forum called On-Step where similar technology is used to point telescopes at specific parts of the sky and follow the apparent motion of the stars for astrophotography.
The same issues arise. Gears have backlash, except for harmonic drives. Belts and pulleys have zero backlash and are the favoured method of gearing up a small stepper motor to provide sufficient torque. Or just to link the drive to the driven 1:1.? Harmonic drives are ace but kinda spendy for most of us. There are a couple of builds in the gallery that use them.
Technology from 3D printers is heavily leaned on in the form of various supported motor drivers. Mostly of the silent stepper stick variety. They have a fair bit of intelligence built in and can change the way they drive the motor to optimise it's use for a given task. Microstep control features quite a lot in this. The TMC2130 is well used and the TMC5160 or the S109 can handle more current. The TMC2209 shows promise but the clone makers haven't settled out a standard format yet.? 3D printers are also often used to print parts and cases.
Cheap microcontrollers are used to run the On-Step software. There is a range of options with varying cost and capabilities. The ESP32 is well favoured at the moment. Good bang for little bucks.
The software to run it all is written by the group founder with help from others and feedback and testing from all users. It uses GitHub as a repository for development of the open source code.
The purpose of this snapshot of another group is not to advertise that group but to suggest that as a development model it has worked very well to achieve a similar goal with similar tech. I'm sure some of what they use would be helpful here. You have a lot in common.
They have the same intelligent, rational approach and discussion that happens here. Like minds. I think that develops in these groups because you can't blag a machine.
Ant?
|
Oh yes, the motors used are from the 3d printing world too. Neema17 is a popular size although there are larger and smaller.
Ant?
|
A mill can be viewed as a subtractive 3D printer. The tasks and automation are very similar.?
|
Thanks for the replies!!
Rex, yes I wondered about slop in the gear.
I cannot see where any loading to the encoder would come from, of course I have not shown how I was going to mount the encoder and gear, I need to get busy drawing the mounting up.
I will use the need for the drawings as the final reason to learn Fusion 360.
Would the #RELS run with a single pulse for spindle speed? Even 8 pulses would be relatively easy.
I could just mount 8 magnets on the spindle gear, they would not even have to be accurately spaced if the #RELS just needed to see 8 pulses.
Ralph
A mill can be viewed as a subtractive 3D printer. The tasks and automation are very similar.?
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Hi Ralph, From what I can see from reading the Arduino code it looks like it needs at least the same number of pulses from the spindle as it needs to send to the stepper motor.? The code I was looking at (pretty old now perhaps) uses a 200 step per rev motor, 4x micro-stepping for 800 steps per rev so the 1800 lines per rev are important. ? I think that's why you can turn the spindle in either direction and the stepper motor tracks.? It's a totally different approach from MACH3 and my ELS.? Even what the code does and how it's written is totally different from my ELS. ? John Dammeyer ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Ralph Hulslander
Sent: December-10-19 11:10 AM
To: [email protected]
Subject: Re: [digitalhobbyist] Step #1 Encoder? Thanks for the replies!! Rex, yes I wondered about slop in the gear. I cannot see where any loading to the encoder would come from, of course I have not shown how I was going to mount the encoder and gear, I need to get busy drawing the mounting up. I will use the need for the drawings as the final reason to learn Fusion 360. Would the #RELS run with a single pulse for spindle speed? Even 8 pulses would be relatively easy. I could just mount 8 magnets on the spindle gear, they would not even have to be accurately spaced if the #RELS just needed to see 8 pulses. ? A mill can be viewed as a subtractive 3D printer. The tasks and automation are very similar.?
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Ralph, here's a scenario. The lead screw is advancing the tool toward the work. The drive gear is pulling the driven (encoder) gear. The tool engages the work and the spindle slows. The drive gear slows and the driven gear momentarily rotates ahead because of inertia in that gear. The motor recovers and the spindle speeds up. The drive gear moves faster to again pull the driven gear.? There may be a small harmonic oscillation as the two gears "bounce" back and forth.
As I said, the slop in the gears likely exceeds your encoder steps, so this oscillation may adversely affect your stepper motor timing. You must determine whether the "lost or inaccurate" steps will cause enough inaccuracy to be relevant, but you do need to understand why a low inertia, constant speed drive is preferred.
It's your call.
Thanks for the replies!!
Rex, yes I wondered about slop in the gear.
I cannot see where any loading to the encoder would come from, of course I have not shown how I was going to mount the encoder and gear, I need to get busy drawing the mounting up.
I will use the need for the drawings as the final reason to learn Fusion 360.
Would the #RELS run with a single pulse for spindle speed? Even 8 pulses would be relatively easy.
I could just mount 8 magnets on the spindle gear, they would not even have to be accurately spaced if the #RELS just needed to see 8 pulses.
Ralph
A mill can be viewed as a subtractive 3D printer. The tasks and automation are very similar.?
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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Thanks John, I still have your ELS in mind.
Here is a very very rough starting idea for mounting the encoder and the gear:
Ralph
On Tue, Dec 10, 2019 at 2:22 PM John Dammeyer < johnd@...> wrote: Hi Ralph, From what I can see from reading the Arduino code it looks like it needs at least the same number of pulses from the spindle as it needs to send to the stepper motor.? The code I was looking at (pretty old now perhaps) uses a 200 step per rev motor, 4x micro-stepping for 800 steps per rev so the 1800 lines per rev are important. ? I think that's why you can turn the spindle in either direction and the stepper motor tracks.? It's a totally different approach from MACH3 and my ELS.? Even what the code does and how it's written is totally different from my ELS. ? John Dammeyer ? ? ? Thanks for the replies!! Rex, yes I wondered about slop in the gear. I cannot see where any loading to the encoder would come from, of course I have not shown how I was going to mount the encoder and gear, I need to get busy drawing the mounting up. I will use the need for the drawings as the final reason to learn Fusion 360. Would the #RELS run with a single pulse for spindle speed? Even 8 pulses would be relatively easy. I could just mount 8 magnets on the spindle gear, they would not even have to be accurately spaced if the #RELS just needed to see 8 pulses. ? A mill can be viewed as a subtractive 3D printer. The tasks and automation are very similar.?
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
I totally agree with Rex.? You do not want any oscillation between spindle and encoder.? ? When I started my ELS project the one thing I could not do was find an encoder with a bore capable of fitting around the spindle and the collet draw bar.? I could have one made but the cost would be $70 and I had to buy 100. ?Also at the time, (2007) inexpensive bearing mounted quadrature encoders were way too expensive compared to our target price of $150 for the ELS kit. ??Even now high quality encoders are into the hundreds of dollars. ? Anyway, this was my initial approach that slipped over the end of the spindle. 
? And fit through the hole in the cover. ?Just had to screw on the disk afterwards and then use the cover mounting screws to hold the sensors. ?  ? The CAD drawing shows what the disk would look like.? But in the end I just couldn't mount it securely enough and I didn't want to try and make a fibreglass cover to go over everything in place of the cast cover. ? John ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Ralph Hulslander
Sent: December-10-19 2:04 PM
To: [email protected]
Subject: Re: [digitalhobbyist] Step #1 Encoder? Thanks John, I still have your ELS in mind. Here is a very very rough starting idea for mounting the encoder and the gear: ? On Tue, Dec 10, 2019 at 2:22 PM John Dammeyer <johnd@...> wrote: Hi Ralph, From what I can see from reading the Arduino code it looks like it needs at least the same number of pulses from the spindle as it needs to send to the stepper motor.? The code I was looking at (pretty old now perhaps) uses a 200 step per rev motor, 4x micro-stepping for 800 steps per rev so the 1800 lines per rev are important. ? I think that's why you can turn the spindle in either direction and the stepper motor tracks.? It's a totally different approach from MACH3 and my ELS.? Even what the code does and how it's written is totally different from my ELS. ? John Dammeyer ? ? ? Thanks for the replies!! Rex, yes I wondered about slop in the gear. I cannot see where any loading to the encoder would come from, of course I have not shown how I was going to mount the encoder and gear, I need to get busy drawing the mounting up. I will use the need for the drawings as the final reason to learn Fusion 360. Would the #RELS run with a single pulse for spindle speed? Even 8 pulses would be relatively easy. I could just mount 8 magnets on the spindle gear, they would not even have to be accurately spaced if the #RELS just needed to see 8 pulses. ? A mill can be viewed as a subtractive 3D printer. The tasks and automation are very similar.?
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Ralph,
I suggest you forget the RELS but go with John D's system. the single
pulse is easy to handle.
Richard
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On 10/12/2019 19:09, Ralph Hulslander wrote: Thanks for the replies!!
Rex, yes I wondered about slop in the gear.
I cannot see where any loading to the encoder would come from, of
course I have not shown how I was going to mount the encoder and gear,
I need to get busy drawing the mounting up.
I will use the need for the drawings as the final reason to learn
Fusion 360.
Would the #RELS run with a single pulse for spindle speed? Even 8
pulses would be relatively easy.
I could just mount 8 magnets on the spindle gear, they would not even
have to be accurately spaced if the #RELS just needed to see 8 pulses.
Ralph
On Tue, Dec 10, 2019 at 12:26 PM Ant No <cmpaqp1100@...
<mailto:cmpaqp1100@...>> wrote:
A mill can be viewed as a subtractive 3D printer. The tasks and
automation are very similar.?
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill
press, 40 watt laser, Consew brushless DC motors and a non working 3D
printer
|
