Category: CNC-en

The Indymill’s Z-axis uses a lead screw  by design , and not a ballscrew as I would like.  But- that will be changed later.

For now, the lead screw solution will be OK because I will first build the Indymill machine and use the 500 Watt DC engine I already have for my CNC3018 setup.

The leadscrew of the Indymill is an 8mm leadscrew with a brass nut mounted in a 3d printed part that is mounted on the vertical rear of the Z-plate.

And- the drive stepper motor is mounted hanging on a horizontal plate on top of the Z-plate.

The required motion is exchanged to the leadscrew with a pair of 8x10x22  treehed wheels that are coupled with a GT2-10 mm wide 200 mm long belt.

The change I made to the original setup is to use an original 8mm lead screw bearing on top, under the horizontal plate.

I did not particularly like the original setup with an 8mm bearing in a 3d printed holder, and an 8 mm lockup ring under and above this bearing.

I had to machine the pro-bearing to fit the Indymill’s mounting holes and get  the threaded drive screw nicely centered.

In this post, you can see how I changed the original Indymill to more rigidity by using the original 1605 aluminium nut holders for the 1605 ball bearing screws of the Y axis, and how I made use of the BK12 and BF12 ball bearing blocks instead of the 3d printed parts like in the original build.

When building the frame, make sure that you do not initially screw anything tight.  Follow the steps that apply to any build:

1. Make the footprint square by measuring either with a good 90 degrees angled measuring hook OR measure the diagonals against each other and make them alike.  Then, tighten all corner screws .
2. Re-measure the footprint’s left against right length and also front/rear length. If there is any difference here,  a) take everything apart and b) make sure you have equal sizes for your build where this is required.  OR, if you have a non-standard build, make sure you build according to specs sizes. The, do 1. again.
3. For a lineair rail: use a ruler that is specifically made for your type of rail  You can 3d print one or buy two aluminium ones.  ALWAYS use at least 2 rulers!  With the rulers in place at 20% from left and 20% from the right,  after you have installed the rail loosely with the screw in the nuts, tighten the screw a bit but not too stiff..  We will get back to these screws at a later stage.
4. Put the connecting piece on the motor’s axle (8mm side) and tighten this well.  Preferably, use some loctite on the axle but don’t overdo it.  Be aware that you need to testfit the BK12 first.  make sure that the connecting piece almost touches the BK12’s nut!
5. Put the stepper motor and the BK12 connector together, using the 3d printed thin NEMA23 adapter plate between motor and steel plate. Do not yet tighten this too much.
6. Make an original aluminium 1605 nut holder block shorter to fit exactly.  See the picture.
7. Fit the aluminium nut holder block including the entire assembly of the 600 mm long 1605 ball bearing screw on the machine, and superglue the block in the correct position.  Let it dry so it won/t come off. Demount verything except the steel sideplate and the glued aluminium nut holder.
8. clamp the nut holder to the steel plate with a grip vice, just to make sure it all keeps together.
9. Drill 3 new 4mm holes through the steel plate’s lower part ,  drill through the aluminium block as far as possible.  2 holes on the lower side and 1 just between 2 of the top 3 holes,  NOT where the existing hole of the aluminium nut holder block exists.
10. Get the nut holder block loose, if it has not already come off.
11. Tap M5 in the holes of the nut holder block.  You will have come through the big center hole (for the nut) with 2 holes, make sure this gets cleaned up on the inside.
12. Drill the new holes in the sideplates with 5.5 mm drill (to give you mounting clearance)
13. Place the sideplate on the 2 bearing blocks of the linear rail with 4 outer M3 x8 (or x10) screws.
14. Put everything loosely together
15. Mill an end baring block to fit the 1605 ‘s screw end at the front an mount this at the exact center of the small front plate.
16. Now, connect your nema 23 engine to a motor steering device so you can test the setup.  First, turn the screw by hand and it should run smooth.
17. Since you want to have an even height of the side plates, do not alter these unless it needs to be done on both sides equally.
18. Your fixation point is the only non-movable position, at the rear of the frame.
19. Move the carriage to the rear and now, see if you have slack on the M3 screws of the slide bearings AND on of the 3x M5 screw the rear of the aluminium nut holder. If so, first tighten the M3 screws.  Then tighten the M5 screws.  If not, loosen ALL of the linear rails screws ans move the rail a little. If this is possible, tighten the M3 screws of the linear rail’s bearing blocks.  Then, try to get as much clearance on the linear rail’s movement up/down as you can and tighten the 3x M5 screws of the nut holder block.
20. Now, tighten 1 screw only of the linear rail, at the position above the nut holder.
21. Move the carriage entirely forward position.
22. Tighten the linear rail’s M3 screw that is exactly in position above the nut holder (of the ball bearing screw)
23. Now, tighten all screws of the linear rail.
24. You’re done!
25. Check the other side and if the linear rail’s height differs from the other side,  the only thing to do is to start over again, where your slack is in the 5.5 mm holes of the steel plate’s screw holes for the  nut block.  If you play with this, and then adjust the linear rail’s height, you can get it all even.  At least’eventually I got mine right but it took some time.  Have fun!

Things to bear in mind: You don’t want anything out of parallel like a linear rail that is uneven to the aluminium profile on which it is mounted or a ball bearing screw that gets under tension.  There is also another way to see what is happening while you are tweaking the hardware/frame: take the front bearing off and see what happens to the end of your ball bearing screw in the hole up front when you move the carriage.  It can tell you much about what is happening…  It should always stay perfectly centered but I’ve seen it up, down and all other directions.. -)

And- I must say, this build goes quite well. The materials are OK, and the guideline from the build description was very good. Although I never use it anymore.  The build is quite self-explanatory once you start building the Indymill CNC machine.  I also cahnged quite some parts, and made alterations where I felt this would improve the machine to fit my purpose better.

Since Corona was still around (May, 2021) , I had some time available to spend on other things than just work.

I already had an upgraded 3018 CNC-machine with a 0.5 kW spindle motor,

and a simple GRBL 3- axis board that works very well.  But- it would be nice to make a CNC machine that can really work with aluminium and possibly also with copper and brass.  I have already done some research in the past about what sort of CNC machine would be right for my goals. And the IndyMill CNC macine was already on my mind for over half a year.  So-last week I ordered the manual and the steel plates

for the build and ordered some other parts from Ali.  I also have quite a lot of parts on stock, from my 3d printer supplies.  The Nema23- motors and the extrusion, motherboard, drivers, power supply, switches and probes are already available.

The required printed parts are being printed right now (early May-2021). I am printing all the upgraded STL’s, latest version as these are freely available  on Thingiverse (just search for IndyMill) .  And then you see the power of sharing: the design was already great, and with the upgrades it got even better.  The upgraded versions of the mounts for the linear bearings are really a lot sturdier than the original design and the new endstop holders are very handy to have.

I roughly calculated the costs for building this machine and it was a lot cheaper than buying a similar CNC machine of this size.  If you purchase wisely, the costs for all materials can be just under Euro 1000, if you follow the original BOM and including the 1.5 KW air-cooled spindle motor with regulator…

If you want to install another board than the standard Arduino UNO with the standard Arduino CNC shield,  this can set you back an additional amount of 120 to 500 Euro’s.  I use a FLY_CDY_V2 with Mellow’s original TMC2209 stepper drivers. DO NOT FORGET to set the switches on the underside of these steppers to ON if you want to use sensorless homing!

My add-ons  to the original build:

1. Currently I use a 10 Amps detachable 24V PSU, will become a 30 Amps one.
2. Sesorless homing with the use of a FLY-CDY-V2 motherboard and TMC2209 stepper drivers.  This works awesome but I moved on to add endstops and make a more stable and exchangeable setup.
3. Original  mounts and usage of the ball bearing screw nut’s holder, and of the BK12 nd BF12 original bearing holders to keep the ball bearing screw from moving the wrong way.
4. Altered Z axis setup with a better nut holder, and a better top bearing
5. .
6. Closed loop NEMA23 stepper motors drivers MKS Servo57A V1.0 will be fitted to the rear of the steppers, still to be mounted but will conflict with sensorless homing

   

7. 10 mm GT2 200mm belt between the Z motor and the Z-leadscrew with GT2 10mm wide 16-teethed wheels
8. Add a ‘CNC pendant’ manual control device.
   • On the Duet support website a project is available to convert such a device to a serial interface, with a programmed Arduino (pro) mircro or -nano built-in the device:
9. Solid connection plate between the rear side of the upper and lower linear rails of the X-axis. Still to come.
10. Piezo-probes on all axes’s start- en end positions, instead I first setup the FLY CDY V2 reprap board with TMC2209 and sensorless homing, and later with mechanical endstops.
11. Coolant mist installation and fluid gathering-, pump, reservoir et cetera is ordered. Stll to be installed, and the pumps were not supplying sufficient pressure for the flood mist, have to look for another solution.
12. Independantly driven (and independantly finetuned homing) Y-motors to prevent any possible problems between left and right. This works flawless with the FLY_CDU_V2 reprap setup but it took me quite some hours of finetuning to work with the 3.5 kilogram heavy spindle motor…
13. 2080 profiles all around (also front and rear) with 4 extra-wide corner brackets underneath.  I chose to implement this differently with 3 additional bottom connections and corner brackets, since I need the front of the frame to be low and give way to the spindle vacuum hose.

    

14. Smart enclosure with Scheppach vacuum cleaner connection like this example from https://www.shophacks.com/cncenclosure.html#/  THIS IS REALLY NEEDED!

    

15. Protecting guards for all leadscrews and linear rails (ordered in China)
16. Later if possible: Wheels on the rear or on 1 side and a handle on the front (or other side) to stow and store the machine easier
17. Easily detachable control unit(s) with solid connectors

I started with a FLY_CDY-V2 reprap board to experiment with reprap CNC and the webinterface that has been developed for this setup.

This is achieved with  smart dual homing of the dual Y axes, and gives me a lot more control on the machine. It is also already possible to just send GRBL-based Gcode to the USB port of the machine and use the reprap FLY board simply as gcode-interpreter to steer the machine.  But for now I use the webinterface to upload and run any gcode.nc CNC file, which works perfect!

Picture of the CNC-adapted and already available webinterface for reprap, especially tailored for CNC (by Sindarius, work ongoing):

Pictures are already published about this build!