4th axis for iModela

4th Axis flip and Indexing attachment Parts needed.

I have added some extras to allow for fixing to various brackets/materials.

6 off 3mm hex socket head machine screws.

16 off 10 x 3mm hex button machine screws.

30 off 3mm nuts.

16 off 3mm thin washers.

4 off 12 x 2mm self tapping screws.

Tools that are required and/or ought to have.

Hand grinder of some sort to use 1.5 mm normal drill. (self taper screws) Square.

Vernier caliper.

3mm drill 3mm shank.

2mm drill 3mm shank.

1mm drill 3mm shank.

3mm 2 flute slot drill. (preferable).

Allan keys to suite.

A4 sheet of polycarbonate.

Other run of the mill tools.

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you may want to get a 1/8th spindle to be able to use easy obtainable drills unless you can get the drills in 3mm shanks.

PRINT PDF FILES. First of all printout the 2 pdf files, one is a printout of the dimensions to give an idea of the sizes required for the needed plastic rectangles. Make sure to setup your printer though, the printer should print 0ne –one, not having `adjust size to fit page` for instance, use the dimensions on the printout to check the size s have turned out correctly. Paper is `A4` size.

The second printout is the blueprint of the parts that are to be cut out, the printout needs to be cut out along the grey lines shown as accurately as possible. The cut out paper rectangles are then used to cut out the plastic sheet blanks . Note that you need to cut out `C` on the boarder of the rectangle not just the grey line this is the only exception this is because the part is too big for the imodela to cut these edges, where to cut is shown on the diagram.

CUT OUT PLASTIC BLANKS The idea is NOT to cut out the individual parts from the sheet as we need the accuracy of being straight and at 90° to various things.

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So just use the rectangle blanks and place them in the centre of the cutting area of the imodela table and fine tune the position using the coordinates given on each rectangle drawing as and when required, then use the given cutting path files given to machine out the parts. Try not to leave excess material on as if the imodela needs to cut through using the whole dia width of the cutter it will leave a jagged edge (caused by too much flex ).

POSITION and STICK ON BLANKS We will start with part `A`, Position the cut out drawing on top of the plastic blank on the imodela table in the centre of the cutting area, you can check that the blank is correctly positioned by putting a pointed bit in the spindle and using the coordinates as shown on each blueprint rectangle.

Note: place the blanks in the centre of the cutting area do not use the table edge as a reference as each imodela may be assembled with a different table position.

I think I ought to go into more detail setting up the blanks as this is one area that is very easy to make mistakes and material as well as tools can be scrapped.

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When positioning the spindle while holding the pointed guidance tool, first set the `control` program to `machine coordinates` and then using the manual controls move the spindle to the coordinates for the appropriate job at hand, then position (not stick yet) the plastic blank together with the drawing on top, putting the correct position underneath the pointed guide tool,

this gives a rough idea where to place the blank, gently open the imodela up and make sure that the blank is square to the edges, (a vernier gauge is good for taking measurements here) then draw a pencil line on your scrap material underneath in two of the corners so that you can lift off the blank and then replace it when you now put on your double sided tape and stick the blank down permanently , next check and re adjust the pointed guide tool over the correct coordinate accurately make sure it is `bang on target` , if you need to adjust it we will use the ` user coordinates` to correct things, so set the machine to `user coordinates` then zero the `x, y` this then makes the position of the coordinates to x0,y0 BUT THIS IS NOT WHAT WE WANT TO MACHINE WITH, now we need to use the same numbers from the coordinates in reverse i.e. As a negative number so again manually

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manoeuvre the guide tool back towards the direction of the machines original zero position, it is at this point you again zero the `x, y user coordinates` and you can now test if all is well, if you manoeuvre the guide tool back over the diagram/blank you hopefully should see that the actual `user coordinates` setting figures shows the same figures as the coordinates given on the drawing diagram, if this is so, your good to go, if they are different go back and find out where things went wrong. The only setting to do now is the tool `z` axis setting in due course .

THE PROGRAM SETUP o.k. now down to the interesting bit, I am assuming that you are using a scrap layer of plastic between the table and our partsto-be (at least 3-4mm thick) and that we are sticking them together with double sided sticky tape. Though I like to use balsa wood as it is cheaper and does not wear the cutter away unnecessarily .

Start up the `creator` program, start by first setting the `preferences` to mm and the drill depth to be 1.5mm (to make sure the point of the drill goes all the way through) then set the material depth to your material thickness (hopefully 5mm), `open` the file called `A cut-out ` you should see the intended parts together with the tool paths shown so now go down to the `cut` button this will open the tool setup page, select the `pointed drill` tool (we are going to do drilling first) and check that you have 3mm for the drill even when you’re your using a 1mm,2mm and 3mm size, material = acrylic.

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Now we will first do a check, so select the `3D preview` button and you should see the `virtual modela` program start up for you to run and drill out the 3 holes. (red holes on a blue material indicates a cut all the way through the material).

O.K. now start up the `imodela control` program and switch on the imodela, before we put in ANY tool bit in (take out the pointed bit!) we will do a dry run of the program tool paths.

While still being in the `creator-tool setup`, select the `cut` button (not the `cut` button on the front page) and the imodela should try to drill the hole closest to the back and to the right hand side of the blank so if it is anywhere else something is wrong.

THE DRILLING Next we will try the actual drilling. Although I have a more powerful motor than the standard one, I have lowered the output to something similar so that I could duplicate the standard motor, it would appear that you are going to have to drill the holes in 3 passes so I suggest trying 1mm, 2mm, 3mm drill bits, I suggest that you alter the drilling settings, these setting are found in the `milling parameters` (don`t ask me why it`s called that for drilling!).

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changing the `tool down speed` smaller something like 30mm/m and the `cut in amount` to 3mm, one more point, each time you setup the tool make sure you `save` the setting as the program will change it back when you close the window! And each time you change the tool bit type or operation make sure you do the same as the program will change it back when your back is turned!, so every time you come back to this setup all you need do is `load` your settings.

All you need do now is replicate all operations with the same settings but install the different drills as required and do 3 passes. I guess you are going to have to replace the spindle with a 1/8� size so you can use the 1/8� shaft drills.

So now lower the Z axis a reasonable amount leaving enough down travel left to do the drilling, around 8+mm should be about right (it has to go further than your material thickness), insert the first drill, allow the drill bit to drop down to the material surface then tighten up, and zero the `Z` axis. o.k. now do a proper run by selecting the `cut` button and if all is ok it should start to drill.

After the first batch of holes have been drilled check the depth of the holes to see if they have gone through enough, if you need a bit more depth just go back to the `creator` program and in the preference setup make the drilling `through hole depth` to something like 2mm, the software will do the rest.

NOTE: if the drilling path appears to be cutting at the top of the `Z` travel above all the holes, this could mean that you setup the spindle too low and the machine tried to compensate and drill down further than the `Z` is capable of so by default it rises the

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spindle but keeps on traversing the x and y axis! (guess it is a safety feature!).

NOTE: if the drilling operations stops and the spindle rises and stays there it is likely that the drill is under too much strain and caused the imodela to cancel the operation so you will have to use an even smaller drill or change the drilling settings, to carry on drilling, just redo from the start with the smaller drills.

It would appear that each drilling operation should take 2 min to complete.

As a side note I do not recall reading what the lights on top of the imodela represent (but if it is stated some where I must of fast forwarded through the manual) the white lights on top of the imodela represent the speed of the motor and they go out one by one as the motor slows down, when they reach 1 light it will stop the imodela. So when the machine is struggling you can tell how far you can push it by watching the lights go out!.

ROUTING/MILLING Now we will do the milling /routing operations, go back into the `creator` program select the `cut` button to get you into the tool setup page then select the flat square tool icon, now you can select the diameter of the cutter of choice I’m assuming a 3mm , check that the material is still acrylic, now select the `milling parameter` button and in this page the settings are wrong as standard! If you look at the `cut in amount` for the roughing and finishing are backwards but I think even after changing them you will find the standard a bit too aggressive so make the `cut in amount` for roughing 0.2mm and finishing 0.2mm and make the `tool down speed` a bit slower say to 40mm/min. you could take a dummy run by using the `3D preview` if you wish.

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Now carry on as you did with the drilling , the machine should start cutting out the large part first. Program indicates that it will take around 3 hours to finish drilling and cutting out. but I’m guessing that 3.5 hours is closer to the truth‌.(I gave up waiting and put more power on !), As the cutter is cutting out this requires the cutter to cut at its full diameter (no surprises er!) BUT the machine may struggle, if this is the case try the `cutting in` amount to be less.

You can see the time to complete the job in the `virtual modela ` program, select the `3D preview` button again and look through the menu.

After the job has been completed I would take a few minutes to clean the lead screws from all the dust as they can jam the movement and then give them some grease. This sounds like I’m being `mother hen` but I damaged a job and had a few problems of the machine cutting through the middle of my job at a depth of 3mm in one pass, it turned out that I had the lead screw jammed with dust and the imodela thought it was in a different place. So now you know.!

O.K. now complete `B` `D` in the same way, always do the drilling first, always check those tool settings, do a dummy run to see if it starts up in the right place, always clean between jobs, clean up your cutter from the sticky tape that is going to be on the end!

Keep in mind that if you only put portions of tape to stick the blank down with, remember to put the tape under the needed parts so that when they are cut out the pieces are still stuck down and not left loose getting caught in the cutter!

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Now for `C`, I have left this one until last on purpose because it needs more attention.

The first thing we need to decide is going to be `a bone of contention `because the whole finished 4th axis/indexing head/flip device is going to need fixing to the imodela table by….screws!!....i can see you all cringing in horror but I have put some thought into the odds whether to stick or screw, sticking I see being troublesome, 1) there is not much room for sticking it onto, 2) if it is stuck down to be strong enough it is going to be a problem to get off without cracking it across the narrow bit, 3) you need to be able to take it off and put back on in the exact same spot which you can only do by screwing, 4) the imodela table, if like mine is NOT straight as in level, it is bowed so we need to handle this by using packing pieces if needed which can only be done with screwing.

5) it makes the imodela table more rigid.

I know this is going to be a problem for you guys to accept but the table is not that very good anyway, it flexes, it`s bent, it can be easily replaced, and it gives an attaching feature for other things , sooo……….just, screw the damn thing down.

But I guess if push comes to a shove I have to say that you could possibly get away with sticking it down.

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Ok, so to start off first we need to assemble some of the parts.

1. Take the plastic blank rectangle that is used for `C` and sand down 2 of the edges so that they end up being straight and at 90째 use a square to get it right (hopefully you cut the blank out with a saw accurately!), take this 90째 corner and position it at the front left corner, the other 2 edges will be trimmed later on.

2. Take a part from `D` (call it a runner) and position it along the edge of the front edge of the blank `C` and hold in position with some sticky tape on the ends and using it as a template drill the holes out by hand using such as a dremel grinder or drill.

3. Then screw the runner on as in the picture after removing tape.

4. Take the table off the imodela and position the table and the parts as per the picture (you may , if like me, have to remove your scrap layer as it may be too thick), then position the other runner on and stick down, then drill out the other holes, then screw on this runner as well after removing all the tape, the table should be just a slide fit, not loose, if there is some play you may have to file/enlarge the holes to allow the runners to be assembled tighter.

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Note: if you have the scrap layer still on the table make sure that it does not protrude over the edges of the table, it is the table we want to align to not the temporary scrap piece.

5. Now reassemble the table back on the imodela and now position the assembly on, making sure that your scrap layer is thin enough to allow the front edge to align against the imodela table and thick enough for the tool setting in the `creator` preferences of 1.5mm past the thickness of your material!.

Note: that you have some tape under all the edges and the other parts you will then be sure that the parts do not drop off and float around to get caught in the cutter.

Note: that it would be ideal to have front and back runners close enough to hold the imodela table snug but the table and the parts are likely to have a taper leaving it slack, so you could loosen the BACK runner and move this in a bit…never loosen the front runner from now on as it will be used for reference alignment .

6. Now insert a pointed bit and this time, align the drill hole on the diagram with the given coordinates placed on the assembly and stick it into place.

Use the same alignment / setup method as you did before.

7. Check the material thickness is at 5mm in the software setup and the tool distance that it travels beyond that point is something like 1.5mm to make sure the drill passes all the way through.

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8. Start with the 2mm drill pattern (advised to do a simulation first) and make sure to set `acrylic`, the `drilling choice` and size, in the `milling parameters` use the drilling setup as before.

Note: the drill pattern shown in the right hand window in the `creator` program will only be visible (red dots) when the correct drill size (2mm,3mm) is selected, when you select the 3mm drill, a different set of holes are shown.

9. If you are going to start drilling holes with 1mm, use the same setup as you would a 2mm drill, the only difference is that you have inserted a 1mm drill in the spindle, you then repeat the same pattern setup for the 2mm.

10. After which you can then follow with the 3mm drilling, changing the setup sizes where needed.

Hopefully all has gone to plan and you need to route out the parts so as before change the tool to your chosen cutter and machine out the remaining parts, but do not remove them off the table yet as we need to use the square part as a jig.

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Take the square part with 9 holes in, that was made in the `B` operation, you can see that 4 of the holes have already had the holes counter sunk and we need the other holes on the reverse side to have the holes counter sunk too, so stick the 9 hold square onto the square that has just been cut on the `C` operation as it is still fixed to the imodela table, but align it as accurately as possible, having the already counter sunk holes underneath. Then use the program file `ver2 counter sink holes` for the next operation. Remember to remount the cutter, zero the `z` axis on the top of this part.

After this you can remove everything and cut off the excess material on those other 2 edges (back side and the right side) clean all the edges with a razor blade or similar to remove all the fray including the holes as they will have a lip on, then file the 2 triangles on the edges shown.

MORE ASSEMBLY So to start off with, we take the long narrow part with two holes in and cut out a piece of polythene the same size and assemble it to the frame holding the polythene between the two parts , the polythene is temporary in case any glue leaks out and tries to glue parts that should not be glued.

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Next, we now need to glue one of the square cut outs onto the main frame as per the picture. Using a flat smooth surface (maybe a piece of the polycarbonate left over) you can keep the covering on to stop any escaping glue from sticking the parts to the flat surface. I suggest using various left over polycarbonate pieces to use as packing, to help position various parts at the correct heights. Put some double sided tape onto one edge of a square then position the 3 holed square onto the frame (as shown) Sticky tape

polythene

then push the tape + square up to the 3 hole square, this sticks the two parts together at the right height and position and they are now forming a `T` ready for gluing.

So now apply glue (where shown) and hold in position until stuck.

Next glue the 2 triangles on and leave to set over night before removing the sticky taped on square, you should now have a perfectly positioned bed at 90째 in all the 3 axis to which you can screw various materials to.

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glue

Now the point has come to attach your completed 4 th axis to the imodela, you may of noticed all the work done to the making of this 4th axis attachment has been from the left hand side of the machine but due to the shape of the imodela I was not able to fix the finished assembly actually on the left side as it would not traverse back and forth on the `y` axis without hitting the imodela electronic casing that forms part of the body work and I only noticed this after doing most of the design work and as I did not want to go through yet another redesign I have decided that it would be best to attach the assembly on the right hand side instead.

You can now finish off gluing one of the table fixtures as shown.

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Then insert the nuts into all the holes, I have designed it so that the nuts are a tight fit and don`t drop out.

As there are many ways in which to attach things to a jig such as this, I have started off with these 3 to give an idea and should be able to cope with most jobs.

When mounting these fixtures, they are not a tight fit onto the frame (not enough accuracy in the imodela!), the idea is to position them pushed up towards the front (or back) every time you rotate the fixture and as the holes in the frame are 4mm there should be enough slack in the screw hole to allow some movement of the screws before tightening up.

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You can see from the example with the blue wax plate not only can you attach the fixtures for indexing round in 4 positions but you can also use the large cut out area as it is also cut accurately enough for positioning larger pieces to enable you to `flip` the work piece.

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cut out lines

C

A

cut out lines

D

x 14 mm Y 18mm

X axis 41 mm Y axis 4 mm

cut out lines cut out lines

cut out lines

cut out lines

you can use a pointed bit in the spindle and using the coordinates of each rectangle to check that the rectangles are centered before routing out or drilling.

x axis 3 mm y axis 13 mm

B

X 15 mm Y 7mm

cut out this sheet on the lines. (`c` is cut where shown) use the cutout rectangles as templates to cut out the plastic sheet. place the plastic rectangles in the centre of the imodela table

cutting area

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78

This sheet gives some of the dimensions to give some idea as to the sizes of the parts.

It also enables you to check that the printer is printing 1:1

3

26

15

12

26

30

6

8

3 40 10

26

26

20

26

26

54.50

3

60

78

41

26

79

6

2

2

3

3

3

78

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