Build continues and upgrades plus review.

The Router I am running is:

Marchant Dice MDL-2-TR model which has a cutting area (mm) of Y=250, X=220 (gantry), Z=50.

The original set up had the the Z mounted on the side towards the Y motor mount and I found that limited travel even further than the above measure. So I changed the position of the Z which allowed all the weight to be more central as well as the slight increase in cutting area. The only down side is that I had to go into Mach3 and inverse the X axis travel set up. It was not a big problem.

I am currently running Motion King 23HS8603 Nema23 motors that are 1.4Nm. Looking to upgrade to 1.8Nm so that can move a bit faster.

Using a Kress 1050 FME router for the spindle and it cuts fine though looking at the quick change options being offered by a few different folks.

I am using DIYCNC boards which are the PCPPS-3 and the older DVR25 driver boards working wonderful and looking to at ways to slave the spindle to Mach3 (Suggestions and directions welcome on this one).

As stated using Mach3 to control the mess and it works wonderfully. Right now using soft limits and looking at which way i want to mount the limit switches I have to get that bit of added security in the system.

Using Sorotec milling bits and Dremel routing bits. Both are working wonderfully to spec and getting a very good life span out of them.

List of to do's:

upgrade to 1.8Nm Nema 23 motors
Limit switches
Mounting a vacuum uptake near the nozzle so that I don't have to directly babysit as much as currently.
Increasing Z axis depth by minimum of 30mm.
Increasing the rigidity of the gantry to fit the set up I am using
Looking at a tool changer for the Kress and if so going to add a sensor so that changes are calibrated when used.
Setting up the ability to control swarf from cutting materials other than wood which will take a separate vacuum collection point than the one currently used (this runs in to a space issue but will find an answer).
Shifting over to Ball screw of the Y and X axis.

I will get some footage up once I have finished the maintenance on her and get some cutting going.

I have already in the old config' gotten some very nice pieces done for harmonicas and concertinas.

At some point and time start building the larger Gantry router for the larger projects.

Michael

Well let's see,

New Nema 23's from Zap has speed up to 1200mm/min with no problems (anything above 1400mm/min and have a bit of binding problems). Had to cut the tails on both the X and Y for fitting the Claw couplers (Variation on Oldham from Sorotec). A bit under 6 hours of work and have the table level to 0.05mm +/- 0.02 (don't have the calipers to get tighter at the moment). Also taking the dive into the arcane world of feeds and speeds and realizing that i am going to have to be able to slow down the Kress 1050 or get another motor as it spins wayyy to fast which is one of the reasons i have been having a bit of burn problem with some of the woods I have been working with.

I have found a lot of resources scattered around the web on the matter and slowly building my own tables for metric to match the bits I use and than testing the table to see how true they are to real life and adjusting as needed.

Other than that doing well.

Michael

PS anyone know a good source for extruded aluminium for frame building and what i would be looking at cost wise for either a trapezoid screw or ball screw for a 120mm travel Z axis. As i am looking at increasing the Z and with it may be adding a 4th axi to the machine.

Thanks for the link.

Michael

Okay,

Very serious question here, does anyone know if the DIYCNC Spindle 2 board can be wired into a Kress 1050 FME Spindle and if so how? Looking at having to drop RPM as the current speed of 5K is just to high when looking at a max feed rate of 1.2m/min and realistic for some bits of .9m/min feed rates for the precision in cut that I am looking for.

So anyone who has an answer to this and possible diagrams for the surgery in side of a Kress 1050 please speak up.

Thanks and have a good day folks.

Michael

I think you are on a hiding to nothing as the kress is a router and designed for high speed operation.
The 2 options that spring too mind are gearing and a single phase inverter to lower frequency.
Have you thought of using single fute cutter that will give slightly lower cut rates.
Most people are trying to speed the spindle up, first time I've heard of trying to lower it!

Peter

The problem is heat. To fast of RPM versus Feed rate and heat can build up which when dealing with wood and acrylic is something you don't want. The other option is decreasing cutting depth but at the speed I am running at that will seriously add to cutting time. So trying to figure a way to get rpm's under control to get closer to a good chip load.

Thanks for the ideas though.

Michael

Well got the protective sheathing for the wires on, trimmed and set up the connections again. Tested the movement and such, You know watching the machine you have been working on move at 1975mm/min is a bit scary when you are not really thinking of what that speed looks like on a machine in motion. It also means that i might be able to get to realistic cutting speeds for the acrylic not to melt with the rpm's the Kress puts out. A bit scary but interesting. Than again stepping up to this level is what I was aiming for so just need to insure safety equipment works and drive on.


Michael

Oh will be doing cutting tomorrow and seeing how the finish is at this speed. Also finding out a lot about doing CAM set up. Doing a semi rough pass with Z level roughing and than going back and either doing a finishing set with any of the following: Z level finishing, 3D Planar, or an Equal distance offset cutting set up. Really need to get these tables done for the cutting conditions.

Michael

Build is going well and looking at adding a rotary table as a fourth axis. Anyone got experience in converting one from manual to CNC? If so what motor is most likely best to do this with. Looking at either a 4" or 6" diameter table. Any and all input would be seriously appreciated. Also looking at converting to ball-screws for all axis' as well and thinking that 12mm would do my well for that. This is converting one of Marchant Dice's MDL-2-TR to full ball-screw and adding enough Z to allow for a 4th axis to be end mounted (most likely a 4" the more I look with a MT2 arbor mount option).

It will be mostly used 3d milling, though if the hardened bronze and cast iron gears could take it might do a bit of lathe type work from it. Any suggestions would be great.

Also has anyone wired up DIYCNC's control board to a Kress spindle? If so or if some one knows would greatly like some insight into that as wiring is something that is not one of my strong suits and willing to admit it.

On the software side will be getting BobCAD/CAM V23 Lathe add on for my current package and seriously doubt that I will be up grading to V24 unless either business really picks up or they can show some very solid reasons to do so. But that is just a a hot spot with me and software to begin with.

Hope everyone is doing well and has a very happy Advent season and a Joyous Christmas.

Michael

A bit of an update,

re posting pic's here on the build and giving a bit more info on what I am up to. Also hope to be able to load a video as well. Got the system 4 on line and it is really making a bit of difference with the reduced wire runs and being able to condense things a bit. Have made a few widgets for setting edges on projects for clamping and proving useful. I am going to be milling some of the cable guides and safety switches out of acrylic and that is going well in the design phase (will post the .dxf files when I have them done). So all and all things are moving forward. Bought a 4th axis and will post pics here.

Here is the pic's:Attachment 3773Attachment 3774


Here is a bit of video:http://www.youtube.com/watch?v=p6hRQEUry_g

Well take care and hope to have some more cutting to show shortly. Also can I get permission to post .dxf please.


Michael

Hi Michael,


You should be able to zip them and then upload them. For example . . .

Quote:

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Originally Posted by m.marino

Build is going well and looking at adding a rotary table as a fourth axis. Anyone got experience in converting one from manual to CNC? If so what motor is most likely best to do this with. Looking at either a 4" or 6" diameter table. Any and all input would be seriously appreciated. Also looking at converting to ball-screws for all axis' as well and thinking that 12mm would do my well for that.

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I just started writing a reply to this then realised that I'm a bit too late. Nevermind I'll say a little anyway...

I converted a 6" vertex rotary table to use as a 4th axis. It was easy enough to machine a bit of 3" aluminium bar to fit on where the handle/dial used to and hold the stepper. It's very sturdy, however the 90:1 ratio makes it a bit slow to turn. I think the stepper has worn the worm drive prematurely since the backlash has increased a lot from new.

A while ago I started making a faster 4th axis which I've posted about elsewhere in the forum. That's using tapered roller bearings and will be driven by a stepper via a belt, so will be faster and also strong.

Quote:

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Originally Posted by Jonathan

I converted a 6" vertex rotary table to use as a 4th axis. It was easy enough to machine a bit of 3" aluminium bar to fit on where the handle/dial used to and hold the stepper. It's very sturdy, however the 90:1 ratio makes it a bit slow to turn. I think the stepper has worn the worm drive prematurely since the backlash has increased a lot from new.

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In standard form, vertex rotabs have the worm/handle on an eccentric so you can engage/disenage the worm and also adjust backlash...

Quote:

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Originally Posted by m_c

In standard form, vertex rotabs have the worm/handle on an eccentric so you can engage/disenage the worm and also adjust backlash...

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Yes, the way I converted mine means it still does...however I've tried that and I think the worm gear might be too far gone for that to help.

Quote:

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Originally Posted by Jonathan

Yes, the way I converted mine means it still does...however I've tried that and I think the worm gear might be too far gone for that to help.

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Take it apart and check it. The worm wheel is just cast iron bolted onto the underside, which i discovered after removing several teeth while machining a bit 1/2" thick steel into a 12" round :-/
Someday, once I've got the mill converted, I'll get it converted into a 4th axis.

m_c,

I am in Edinburgh. You are more than welcome to contact me and come over to look at the shop.


Michael

Well been getting some good cutting going (enough to require maintenance duty on the machine beyond normal clean up after a days work) and looking to do some upgrade work on the Wee Beastie.

Looking for input on the best method for upgrading to Ballscrews and also raising the Z axis while keeping the rigidity up (if not increasing it). I am looking at either Alli' plate or extrusions and would like input there on the Y/Z axis unit (going to raising to 100-125 mm travel to allow the addition of an A-axis to the unit [already have the unit]).

On the Ballscrew front what I am interested in information wise is input on how best to convert the unit I have (a Merchant Dice TR model) to Ballscrews. I have been looking at Zap and a few others and would like in put on the best method for setting up the bearings for the ballscrews and if it would be wise/possible to upgrade to 20mm ballscrew from the 16mm trapezoid screw that is currently there (this is on the X axis, on the Y and Z I plan to upgrade to increase rigidity a bit).

Still cutting and business is improving so things going well. Hope everyone else is having a great day and take care.

Michael

Quote:

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Originally Posted by m.marino

Looking for input on ... raising the Z axis while keeping the rigidity up (if not increasing it). I am looking at either Alli' plate or extrusions and would like input there on the Y/Z axis unit (going to raising to 100-125 mm travel to allow the addition of an A-axis to the unit [already have the unit]).

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Just make it as strong as you can. Extrusion is great if you can afford it. Plate is the worst solution in terms of bending for the gantry sides. Aluminum or steel channel or box section will be much stronger with forces parellel to the Y axis for the same mass. Irving posted an excellent spreadsheet about it somewhere...

I would be inclined to increase the distance between the bearings on the X axis. This will of course loose travel but it may be neccarcy to keep it rigid.

You could consider just simply raising the Y/Z axis to fit the A axis and leaving the Z axis with the same travel. That way you will only have the bending of taller gantry sides to worry about. When you don't want to use the A axis drop it down again. The slots in the aluminium extrusion make this easy to do and you could put a block of aluminum on either gantry side at the current height to locate the gantry so you don't have to get it level every time.

Quote:

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Originally Posted by m.marino

I have been looking at Zap and a few others and would like in put on the best method for setting up the bearings for the ballscrews and if it would be wise/possible to upgrade to 20mm ballscrew from the 16mm trapezoid screw that is currently there (this is on the X axis, on the Y and Z I plan to upgrade to increase rigidity a bit).

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The eBay seller linearmotionbearings2008 is much much cheaper than Zap. They will cut the screws to length and machine them. I've ordered a few times from them and not had any problems.

The diameter of the ballscrew required depends on the length, and end fixity. I would put a double row angular contact bearing (or a pair of single row) at one end and a standard deep groove bearing at the other. The best way is to have angular contact bearings at both ends, however the critical speed of a 16mm screw, 400mm long (just guessing the size, correct me if I'm wrong) with the above bearings is around 10,000rpm - so plenty! I'm using a 550mm (ish) 16mm ballscrew on my Z-axis and it happily went at 10,000mm/min - it's limited by the motor torque.

Since the critical speed for a 16mm ballscrew is so high there's not really much point using a 20mm screw. You're not going to exceed the load ratings of the 16mm either. Also if you had a 20mm screw the inertia is much greater (the effect is proportional to the diameter of the screw to the power 4), so your acceleration will suffer. The same is true with changing from 12mm to 16mm screws, however ballscrews are much more efficient than trapezoidal screws so you'll end up fine. Thinking about it it's not really an issue since the screws you have currently are 3mm pitch (I think?), which will have to turn faster than a 5mm pitch ballscrew ... so etc... (I think I've written enough!)

Thanks Jonathan,

Definitely some things to think on and thanks for the additional resource.

Michael