Machsupport Forum
General CNC Chat => Show"N"Tell ( What you have made with your CNC machine.) => Topic started by: SimonD on April 12, 2009, 01:03:23 PM
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Seeing all the other 4th axis on here, I thought I would show my rendition of one, along with the tooling plate and CoolJet I made for my Boxford 190VMC.
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Very nice, could you be a little more detailed about your cool jet setup?
Thanks for sharing-
Dave
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The CoolJet is similar in concept to this patent...
http://www.google.com/patents?vid=USPAT5390854&id=khscAAAAEBAJ&printsec=drawing&zoom=4&dq=5390854#PPA2,M1 (http://www.google.com/patents?vid=USPAT5390854&id=khscAAAAEBAJ&printsec=drawing&zoom=4&dq=5390854#PPA2,M1)
The coolant and air is supplied at the same pressure to the nozzle and mixes together so you get fine dropplets in the air stream. The adjuster regulates the amount of liquid in the airstream.
I have made it also remotely adjustable using a RC servo. That way when the machine does a toolchange it can move itself out of the way of the toolchanger and return to the correct position for the specific tool.
Thanks
Simon
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Interesting. Thanks - :)
dave
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Hi Simon,
Is the 4th axis belt driven ? and what is the reduction ratio please.
Tweakie.
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Tweakie,
Yes the 4th axis is belt driven. The ratio is 32:10 Not ideal but the biggest ratio I could get in the small space.
Simon
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Hi Simon,
Nice work! Did you make the 4th axis from scratch? How about sharing some details about how you made it? Is it stepper driven? what is the max RPM?
Did you make the spindle yourself? Did you use angular contact ball bearings?
Have you tried it yet? What is held in the collet there?
What is the table travel of your Boxford?
Thanks.
Daniel
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Daniel,
Yes the 4th axis is made from scratch.
It is stepper driven through a 32 - 10 belt drive.
The spindle is a genuine cheap copy of an ER20 2 Morse Taper Collet Chuck (£5 from eBay)
The bearings are Deep groove Radial 6804-2RS bearings, I didn't need a lot of preload so deep groove bearings are perfectly adequate.
I don't use it as a spindle but as a rotary indexer and so have not tried it at speed. I guess it will be limited by the kernal frequency... 200 steps * 10 microstepping * 3.2 ratio = 6400 steps per rev. at 25khz that would be 234 rpm
I have attached a pic of the axis "transparent" so you can see the inside.
Yes I have used it extensively and have not found any problems with it. The stepper is pretty weak but that is to be expected. It is fine for cutting but does not have the power to hold the collet chuck in place while you try and ram the main spindle into it (Yes, it has tried it on a particularly odd hiccup) it just freewheels which is quite nice as it saved the chuck.
In the collet is just a small fixture I use for making RC Helicopter Rotor Cores, a picture of which can be seen here along side the plastic part it replaces.... http://www.byte-sized.com/ebay/DF4_Core_Both.jpg (http://www.byte-sized.com/ebay/DF4_Core_Both.jpg)
To give an idea of scale, it is made from 1/2" bar.
The travel on the Boxford is 190mm in X and ~125mm in Y
Thanks
Simon
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I fly a DF4 & a Walkera 36. Nice job on the rotor core.
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I fly a DF4 & a Walkera 36. Nice job on the rotor core.
Thanks... My DF4 is pretty non-standard now. It even has a complete CNC'd head and 2.4Ghz receiver. The frame and main motor is original though ;D
If you still run the plastic DF4 core and want an Ally one, give me a shout.
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My DF4 is running an E-Sky receiver, Super Skids, Acro 280BB main motor, tower Pro servos and a 10C 2200 ma battery.
Still running a Plastic rotor but not the DF one.
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Simon,
Thanks for the details!
Wow... and that tiny rotor core... is it nice... Well done! I liked id. Was it fully made on the 4th axis with one setup?
How do you generate the gcode for the 4th axis?
What is the bore diameter through spindle? Did you make the housing out of steel?
I plan do build a 4th axis as well (to be used with my Emco F1), but I want to design it such that I can mount it both vertical and horizontal. I want the horizontal mounting mainly because I had to machine large disks few times, that were beyond the travel of my F1's Y axis (100mm).
What belt tooth profile did you use? I used Gates GT2, 5mm pitch on my Compact 5 servo spindle, and was stunned to discover it had backlash. I don't know if it's the way it should be. You can actually see the air gaps between the meshed teeth of the belt and pulley, which is not the case with MXL belts for example.
Daniel
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Daniel,
Yes the rotor core is made in one setup on the mill. The blank is turned onthe lathe to prepare the bottom diameter and that is used to hold it for all the other operations.
The whole core is roughed with a larger cutter and then finished with a 2mm slot drill. even the holes are drilled using the slot drill, the backlash on the mill is good enough to make even 2.5 or 3mm holes acceptable.
I haven't really generated 4th axis GCode. The GCode is "per side" in subroutines and I just rotate to the correct side, then call the subroutine, then rotate again and then call a different subroutine etc.
The spindle is not through bored. The housing is made from aluminium plate. I thought about making the spindle "universal" but decided to dedicate this to horizontal. It is in quite a nice position. Even at the extents of travel the chuck of the 4th axis only just touches the main spindle, so it is fairly "safe" and does not get in the way for any other operations, I can leave it on and don't need to set it up, it just sits there ready for use on a different machine offset.
The belt I used is Syncroflex T5 (5mm pitch) I have not tried to measure the backlash, there certainly doesn't "feel" to be any but I am sure there is some.
Thanks
Simon
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Simon,
Yes the rotor core is made in one setup on the mill. The blank is turned onthe lathe to prepare the bottom diameter and that is used to hold it for all the other operations.
It proves what a powerful tool a 4th axis is! Think could make the part without using a 4th axis?
I would really like a through bored spindle and I prefer a one that I can mount a chuck on. Know where I can find such?
If you say aluminum housing works well for you, then I think I'll go for aluminum as well.
Daniel
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I used to make the core with a manual 4th axis but it was very laborious as you had to be at the machine all the time to turn the part between each operation.
I don't know of any bored spindles for sensible money.
I have a 2 morse taper chuck adapter which could be mounted in the same way and a conventional 3 or 4 jaw screwed on. They are quite common as most of the small rotary tables have a 2MT hole in the middle.
Simon