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  1. #1
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default Turret Mill CNC Controls

    My Kondia turret mill has operated for the last couple of years with a second-hand (cheap) Dell desktop machine and a parallel BOB (Break-Out-Board).
    I use LinuxCNC for the control, and I regard it all as very successful.

    Recently, the Dell became reluctant to start, so I elected to re-work the entire control system.
    New Computer Cubicle, new RaspberryPi 4B 4 GB processor, new ethernet Mesa (7i96) card, and re-use the BOB for more I/O (it connects to the Mesa).
    Existing Leadshine stepper drivers will be retained.

    Also re-purpose original factory control cubicle as the Power Cubicle.
    VFD, stepper power supply, general purpose power supplies, relays for front panel and spindle control.

    In addition, new front panel controls in diecast boxes.
    Control at 12 Vdc using Dia 22 mm ABB push buttons and Idec switches from RS Components.

    Photos show progress on the Computer Cubicle and a test trial of machining the holes for the PB and switch controls.

    The cubicle is an Altronics purchase, borderline on its features, especially the plastic door handle mechanism.
    The backplate is only 1.5 mm so M5 nutserts have been used for component mounting.
    Side penetrations are left to right, top to bottom:
    - four vertical holes for stepper sockets,
    - two horizontal holes for air ventilation out,
    - rectangular opening for VGA, mouse and keyboard plugs,
    - rectangular opening for busway to adjacent Power Cubicle,
    - holes for pressurizing air ventilation fan.

    My current problem is machining holes for the front controls in diecast boxes.
    First effort uses a standard holesaw and a purpose-made adapter to mount it in my small mill.
    The photo includes a 7/8" holesaw, the resultant hole in a piece of aluminium, the diecast box lid and a pushbutton.

    Apart from the general loose fit, I have no anti-rotation feature, generally used for industrial controls.
    I will check the RS catalog to see if they have appropriate washers, the sort with a tab inwards to hold the control and another outwards to engage the panel.

    The PB thread is Dia 21.7 mm, the hole is Dia 22.1 mm, and the flats are AF 20.2 mm.
    But the switches are slightly different, about AF 21.1 mm on some and keyways on the others

    Any suggestions for improving the fit and incorporating anti-rotation ?

    Computer Cubicle 28Jan22 compr .JPGPB Fit Test 28Jan22 compr.JPG

    Keep well,
    John

  2. #2
    Join Date
    Sep 2008
    Location
    Riddells Creek, Vic.
    Posts
    831

    Default

    This is a common problem when fitting 22mm industrial switches, if you can standardize on one particular brand you might be able to get a Chassis Punch to suit the configuration.

  3. #3
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default

    Thanks Techo1, but this is not a production situation - I may never have to do this sort of thing again.

    The RS Catalog has "Mounting Collars" that engage the keys/flats on the PB/SW and two pointed screws angled to engage the panel.
    Could be useful as I think I have enough room for them, but they are expensive.

    The controls on the diecast box are arranged in two rows of four (8 total).
    And I will have a CNC mill soon again, I hope.
    So, I can make a locating strip in 1.6 mm aluminium that locates the controls in pairs - problem solved.
    Close-fitting holes with appropriate tabs to engage the flats/keyways can be pocketed out using appropriate CAD/CAM.

    The holes will be positioned on my small mill using the dials, so should be within 0.1 mm of correct location.

    I can mount all the controls, get the mill re-commissioned, then make the pairs of locating strips.
    Should be a simple job to install the locating strips, just a bit tedious removing all the wired connections to fit the strips.
    Expect to require a minor amount of hand fitting to get perfection.

    Back to the small mill and the holesaw.

    I will update this thread as I progress through the build.

    Keep well,
    John.

  4. #4
    Join Date
    Jan 2012
    Location
    Melbourne
    Posts
    149

    Default

    A22NZ-A-50501 | Omron A22NZ Lock Ring for A22N, A30N, M22N | RS Components (rs-online.com)

    These work quite well, at least with Omron A22 switches. Only need a step drill for the hole.

  5. #5
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default

    Thanks for that Neil317, they are certainly more affordable, but about 3 weeks away.

    Have moved forward, the photo shows the diecast box lid with 8 holes.
    Found a 22 mm holesaw, but it is no better than the 7/8" as it has more runout giving the same result.

    The controls will be, left to right, top to bottom:
    - Coolant On/Off,
    - Light On/Off,
    - Spindle Start,
    - Spindle Speed Set Knob,
    - Jog Spindle CW,
    - Jog Spindle CCW,
    - Spindle Stop,
    - Spindle Direction CW/CCW.

    This is going to be a compact box of controls, I hope they all fit !

    A separate smaller box is allocated for Emergency Stop, and expectations are that another box will display spindle speed.

    Control Panel Holes 28Jan22 compr.JPG

    Keep well,
    John.

  6. #6
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default

    Started to do a trial install of the controls.

    Found some of the buttons have a plastic ring that provides anti-rotation with a projection meant to engage a radial slot in the mounting hole.
    Probably Ok for light duty (like mine), but would need a tighter fit in the hole to be usable.
    Says a lot for the quality control at the manufacturer.
    I got them as two separate deliveries, perhaps there was a design improvement during the intervening period.

    As my holes are not a tight fit, I will proceed with my locating strips.

    My design has hit a snag.
    The switch assemblies are in two parts, the knob assembly and the switch block assembly.
    Separation is achieved by moving a plastic outrigger arm.
    At assembly, the word 'Top' is moulded into the two assemblies to ensure correct orientation.
    My design positions the switch blocks with the separation arm downwards.
    But that puts the knob assembly the wrong way round for a selector switch knob.

    When I install the way intended, the outrigger arm fouls (very slightly) the box lid casting at the gasket seal.
    I think it could be 'coaxed' together, but I will investigate if a re-build of the knob assembly is a possibility.

    Keep well,
    John.
    Last edited by electrosteam; 28th Jan 2022 at 10:58 PM. Reason: Spelling

  7. #7
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,185

    Default

    Quote Originally Posted by electrosteam View Post
    Any suggestions for improving the fit and incorporating anti-rotation ?

    CNC mill?


    In the past, I have used a drill press with a small drill (say 1/16 or 5/64"), drilled a series of holes around the shape, hammered out between the holes with a cold chisel, and filed the hole to shape.

    Of course, it takes ages, is only suitable for a few holes, and is much easier on an ABS case than a die cast one.

  8. #8
    Join Date
    Dec 2007
    Location
    Adelaide
    Posts
    574

    Default

    Is it possible to rig up a temporary enclosure for the controls to get the cnc working and then use that to machine the holes - I've sort of done that on my conversion it's up and running with a scrap piece of Al for the front panel to mount the controls - further work has currently stalled do to other commitments, but once they are out of the way I'll use the cnc to machine the holes and engrave the artwork/labels etc.


    Over the years I've scratch built many electronic projects and the two things that gave the most headaches were chassis cutouts for things like IEC sockets and the control panel artwork/engraving - hopefully those days are over.

  9. #9
    Join Date
    Aug 2006
    Location
    Melbourne
    Posts
    1,105

    Default

    I think the easiest way to incorporate an anti rotation mechanism would be via a small dab of weld preferably with a tig, clamp a piece stainless as a backing plate and then just give it a quick zap along with some filler wire.

    Sent from my SM-G935F using Tapatalk

  10. #10
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default

    Com_VC,
    You have hit a nerve, I would love to achieve small workshop TIG skills, but I think that will for ever be beyond my grasp.

    I have progressed, somewhat.
    The photos show the cable cubicle busway, the two cubicles on the back/side of the mill, and the control panels on the front.

    The E-Stop is the final mechanical assembly.
    Has to come off to paint the mounting spacers, wire and fit conduit gland.

    The main control panel is temporary, just seeing how it looks, and would work.
    Final arrangement will need some structural aluminium brackets and welding (by a friend).

    The cubicles should (!) be in final mounted positions.
    You can see the structural busway tying the two cubicles together.

    Now need to source some suitable flexible conduit.
    Rather fancy the metallic variety, but not sure about where to get it at an economical price.
    Any suggestions ?

    Cable BusWay 29Jan22 compr.JPGControls 29Jan22 compr.JPGCubicles 29Jan22 compr.jpg

    Keep well,
    john.

  11. #11
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default

    I thought I should provide an update.

    The mill has been running for some time now without any problems.
    In regular use and no failures.

    A background problem is the LinuxCNC error message at the start of each session that the internal response timing is a bit off.
    Nothing seen in any job.
    The Raspberry Pi is running the standard (quite old) Raspian LinuxCNC image available on the sources page.
    There is a new Debian image available, and I will soon be trying that.

    The attached photos are very poor, and I apologize for that, but they give you the idea.
    I have to rig up better lighting and stabilize the phone next time.

    The current development plan:
    - purchase a MPG (Manual Pulse Generator),
    - fit a 'Power On' lamp,
    - fit thermal switches for the cubicle cooling fans (perhaps 28 degrees),
    - upgrade the software to Debian,
    - make a stand for the keyboard and mouse.

    Suggestions welcomed for:
    - ebay source for a (simple minimal) MPG.
    - setting for the thermal switches.

    My system won't let me attach photos at the moment.
    I will try later.
    Keep well,
    John.

  12. #12
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    930

    Default

    Got past the attachment problem and here at last, are the photos

    CNC Cubicle 26Sep23 compr.jpgE-Stop Panel 26Sep23 compr.jpgMain Controls 26Sep23 compr.jpgPower Cubicle 26Sep23 compr.jpg

    The cubicles are a bit crowded.
    If I have to do anything major in future, I will build a new floor-mounted cubicle.
    The labels are still waiting on a friends router.
    I will be modifying the doors to make them removable.

    The attachment problem:
    Some time ago, I discovered a problem with my Lubuntu 22.04 LTS install on the office laptop.
    NCViewer opens to simulate a GCode file, but will not browse to allow selection of the required file.
    In this case, the work-around is to copy the file content and paste into the "New File" window on NCViewer.

    Enquiries on Ubuntu Discourse revealed a known deficiency on the current Lubuntu, the absence of a particular driver.
    It is hoped the new release in April 2024 will correct it.
    As NCViewer is the only application used by me that seems affected, I chose to wait until April.
    You can search for "electrosteam" on Ubuntu Discourse if you want more details.

    The Workshop laptop has Ubuntu Mate 22.04 LTS and it allows browsing on NCViewer, and on this Forum.
    So, I am writing this in the Workshop.

    Don't you just love computers,
    Keep well,
    John.

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