[jips]

One of many rules : Avoid re cutting chips

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[handlewanker]

Hi, there's a heap of good advice coming through and I have to agree with it completely, but as I'm more like tinkering with the milling and don't really have any projects to do with CNC, I'll have to think of some to justify buying the machine.

This may offend some people's idea that the capitol outlay should be retrieved in a short time, ROI etc..... or it's money down the drain etc

Basically I'm having fun just learning and creating G code and not particularly worried if it takes time to get there.

I doubt whether I'll ever indulge in a CAM package as the work is just not there, but who knows, creating with Fusion 360 anything is possible once you get into the swing of it.

On the topic of the power draw bar failure........it only operated for tool removal and insertion and during that task after the first repair it worked a few times in the space of 2 hours or so, that means it wasn't being used as a button pushing finger exerciser.

The over voltage supply cooked the brush holding mechanism as it was just a thin plastic plate.......the first failure caused one wire to the brushes to burn through......when this was "improved", the carbon brushes carried more current for longer and melted the plastic.

The motor is a 12 volt permanent magnet field with a wound armature.......very neat and nicely put together, but not suited for the 36 volts it got supplied..........possibly at 12 volts it didn't have enough oomph to push the draw bar down, hence the idea to up the voltage etc, as it only works for a very brief period each cycle.

The main point is, although the PDB activation at the push of a button is pretty, sophisticated and absolutely cool, the manual method I'm fitting for a temporary fix will no doubt be just as effective even if agricultural.....but having to do 3 turns with a ring spanner on a 12mm screw is not the end of the World if it gets me up and running again.

Unless I completely reinvent the wheel and hack the motor to pieces in an attempt to get it to function......that could entail rewinding the armature for 24 volts, but as the amount of wire won't give enough amp flow so a bigger motor would really be the answer..........the problem is the end of the armature shaft has a worm screw cut into it to drive a plastic worm wheel and screw making it difficult to fit a bigger motor per se......and then the components of the mechanism itself could fail with the increased force as they are all made from a Nylon type material.

I totally agree....a pneumatic solution is the simplest answer, but I don't want to go on air unless I really really have to.
Ian.

[jalessi]

Hi, there's a heap of good advice coming through and I have to agree with it completely, but as I'm more like tinkering with the milling and don't really have any projects to do with CNC, I'll have to think of some to justify buying the machine.

This may offend some people's idea that the capitol outlay should be retrieved in a short time, ROI etc..... or it's money down the drain etc

Basically I'm having fun just learning and creating G code and not particularly worried if it takes time to get there.

I doubt whether I'll ever indulge in a CAM package as the work is just not there, but who knows, creating with Fusion 360 anything is possible once you get into the swing of it.

On the topic of the power draw bar failure........it only operated for tool removal and insertion and during that task after the first repair it worked a few times in the space of 2 hours or so, that means it wasn't being used as a button pushing finger exerciser.

The over voltage supply cooked the brush holding mechanism as it was just a thin plastic plate.......the first failure caused one wire to the brushes to burn through......when this was "improved", the carbon brushes carried more current for longer and melted the plastic.

The motor is a 12 volt permanent magnet field with a wound armature.......very neat and nicely put together, but not suited for the 36 volts it got supplied..........possibly at 12 volts it didn't have enough oomph to push the draw bar down, hence the idea to up the voltage etc, as it only works for a very brief period each cycle.

The main point is, although the PDB activation at the push of a button is pretty, sophisticated and absolutely cool, the manual method I'm fitting for a temporary fix will no doubt be just as effective even if agricultural.....but having to do 3 turns with a ring spanner on a 12mm screw is not the end of the World if it gets me up and running again.

Unless I completely reinvent the wheel and hack the motor to pieces in an attempt to get it to function......that could entail rewinding the armature for 24 volts, but as the amount of wire won't give enough amp flow so a bigger motor would really be the answer..........the problem is the end of the armature shaft has a worm screw cut into it to drive a plastic worm wheel and screw making it difficult to fit a bigger motor per se......and then the components of the mechanism itself could fail with the increased force as they are all made from a Nylon type material.

I totally agree....a pneumatic solution is the simplest answer, but I don't want to go on air unless I really really have to.
Ian.

Ian,

What about retrofitting to a actuator like this:



MSI Motors Linear Actuator MSI 1000 Adjustable Stroke 1300lb Load | eBay


MSI Motor, LLC | Linear Actuators

or this

Linak LA23 Linear Push Pull Actuator | eBay


Jeff...

[tmarks11]

... the manual method I'm fitting for a temporary fix will no doubt be just as effective even if agricultural.....but having to do 3 turns with a ring spanner on a 12mm screw is not the end of the World if it gets me up and running again.
Ian.

Why kludge something together instead of just sticking a normal threaded drawbar in there with a nut on the top to tighten it?

30 min with a lathe and you gave your mill operational again.

[louieatienza]

Hi, there's a heap of good advice coming through and I have to agree with it completely, but as I'm more like tinkering with the milling and don't really have any projects to do with CNC, I'll have to think of some to justify buying the machine.

This may offend some people's idea that the capitol outlay should be retrieved in a short time, ROI etc..... or it's money down the drain etc

Basically I'm having fun just learning and creating G code and not particularly worried if it takes time to get there.

I doubt whether I'll ever indulge in a CAM package as the work is just not there, but who knows, creating with Fusion 360 anything is possible once you get into the swing of it.

On the topic of the power draw bar failure........it only operated for tool removal and insertion and during that task after the first repair it worked a few times in the space of 2 hours or so, that means it wasn't being used as a button pushing finger exerciser.

The over voltage supply cooked the brush holding mechanism as it was just a thin plastic plate.......the first failure caused one wire to the brushes to burn through......when this was "improved", the carbon brushes carried more current for longer and melted the plastic.

The motor is a 12 volt permanent magnet field with a wound armature.......very neat and nicely put together, but not suited for the 36 volts it got supplied..........possibly at 12 volts it didn't have enough oomph to push the draw bar down, hence the idea to up the voltage etc, as it only works for a very brief period each cycle.

The main point is, although the PDB activation at the push of a button is pretty, sophisticated and absolutely cool, the manual method I'm fitting for a temporary fix will no doubt be just as effective even if agricultural.....but having to do 3 turns with a ring spanner on a 12mm screw is not the end of the World if it gets me up and running again.

Unless I completely reinvent the wheel and hack the motor to pieces in an attempt to get it to function......that could entail rewinding the armature for 24 volts, but as the amount of wire won't give enough amp flow so a bigger motor would really be the answer..........the problem is the end of the armature shaft has a worm screw cut into it to drive a plastic worm wheel and screw making it difficult to fit a bigger motor per se......and then the components of the mechanism itself could fail with the increased force as they are all made from a Nylon type material.

I totally agree....a pneumatic solution is the simplest answer, but I don't want to go on air unless I really really have to.
Ian.

Something similar to this...
Linear Servodrives Linear Servoactuators - ServoDrive

And they're VERY fast. But it's expensive, I've seen them on eBay sometimes for less than $100 less the servo drive.

[G59]

I totally agree....a pneumatic solution is the simplest answer, but I don't want to go on air unless I really really have to.
Ian.

Then why even bother with a power draw bar. If speed or production is not the goal, then a simple drawbar is best and cheapest.

[ihavenofish]

Why kludge something together instead of just sticking a normal threaded drawbar in there with a nut on the top to tighten it?

30 min with a lathe and you gave your mill operational again.

the spindle and tools arent designed for a normal drawbar. it could be modified, but its a hell of alot easier just got get an air cylinder, like what should have been on there in the first place.

[handlewanker]

No No a thousand time no....air is out as in not an option I want to indulge in.

This evening I fitted a piece of 30mm X 20mm steel bar across the corners of the power draw bar housing with a 12mm bolt in the middle to depress the draw bar.

Two turns with a spanner and I now have a working draw bar.......hand powered of course......it takes about the same time to change a tool as the electric one......a 150mmlong ring spanner easily turns the bolt against the draw bar pressure.......I wonder what that translates into Kg's on the draw bar end?

Eventually the matter will resolve itself when I can find a suitable solution, but for now I'm back in the saddle again.

As there is bags of room on top with the existing mechanism off, I'm working towards having an electro magnet type thruster to do the push.

It's more like an electro magnet as you get more pull the closer the steel piece gets to the pole face.

The last design I worked on had two coils side by side with a spindle running up the centre between them and a steel plate across the top of the coils attached to top of the spindle........the coils will probably work on the 24 volt transformer if the amps are high enough, but with a direct thrust and no form of gearing I think a new transformer is needed......experiment needed here......it only needs to move about 3 to 5 mm or so.

I think 4 coils will work better and be more compact as they can be arranged in a square pattern with the spindle going up the middle between them.....that will double the force........perhaps a neodymium magnet in a solenoid will work even better

Using a small transformer would mean a large capacitor in addition to supply a large current flow, all very doable and nothing too exotic.

I've given up on sourcing an actuator as they seem to have too many moving parts and too much plastic in their build and that's a recipe for failure.
Ian.

[handlewanker]

Then why even bother with a power draw bar. If speed or production is not the goal, then a simple drawbar is best and cheapest.

The short answer to that is a push button works better than a manual fix it.....just needs the right design.

Originally, I was going to build my own design for the mill but Defeng came up with the electric option, so I thought why not.
Ian. .

[louieatienza]

No No a thousand time no....air is out as in not an option I want to indulge in.

This evening I fitted a piece of 30mm X 20mm steel bar across the corners of the power draw bar housing with a 12mm bolt in the middle to depress the draw bar.

Two turns with a spanner and I now have a working draw bar.......hand powered of course......it takes about the same time to change a tool as the electric one......a 150mmlong ring spanner easily turns the bolt against the draw bar pressure.......I wonder what that translates into Kg's on the draw bar end?

Eventually the matter will resolve itself when I can find a suitable solution, but for now I'm back in the saddle again.

As there is bags of room on top with the existing mechanism off, I'm working towards having an electro magnet type thruster to do the push.

It's more like an electro magnet as you get more pull the closer the steel piece gets to the pole face.

The last design I worked on had two coils side by side with a spindle running up the centre between them and a steel plate across the top of the coils attached to top of the spindle........the coils will probably work on the 24 volt transformer if the amps are high enough, but with a direct thrust and no form of gearing I think a new transformer is needed......experiment needed here......it only needs to move about 3 to 5 mm or so.

I think 4 coils will work better and be more compact as they can be arranged in a square pattern with the spindle going up the middle between them.....that will double the force........perhaps a neodymium magnet in a solenoid will work even better

Using a small transformer would mean a large capacitor in addition to supply a large current flow, all very doable and nothing too exotic.

I've given up on sourcing an actuator as they seem to have too many moving parts and too much plastic in their build and that's a recipe for failure.
Ian.

That's because you look at the wrong type of actuator. Check out the inverse roller screw actuator I posted a link to. This will push your entire spindle assembly off the machine if you want it to they're that powerful. And way more reliable.

[tmarks11]

No No a thousand time no....air is out as in not an option I want to indulge in.

Why are you so adamantly opposed to pneumatics?

I couldn't imagine working without a compressor. Hand-held pneumatic tools to prep metals for welding are a must-have.

Would the noise bother your neighbors? There are some quiet compressors out there.

[handlewanker]

"hand held pneumatic tools"........I don't have any......I do have a compressor but all my power tools for weld clean up etc are electric.....I don't do ANY weld prep either as I weld with a plasma welder.

Louie.....I saw your link to the servo actuators........pretty exotic, probably overkill for the SVM-0, not really my idea of something just to pushi the DB down a bit.......I'm working (designing) on an electric solenoid device that is ultra simple and only has one moving part......I just need the wiring requirements to create an electro magnet combination that will provide enough force to do the pushing.....it only has to move approx. 5 mm, so it's going to be very simple.

The manual draw bar actuator I made will get me by for the present....not the ideal solution but adequate for my immediate needs.........oh yeah, one hour to make and it only weighs less than a 1/4 Kg and cost cents to make.

I toyed with the idea of a lever and cam design, but that would be a lot of work for something that is temporary and might end up being on there for years.

At least now I can also get access to the drive belt if I want to change to the smaller pulley.....the belt needs to be changed too and with the PDB mechanism in place on top of the housing, that is a huge job in itself.
Ian.

[louieatienza]

They have one rated to 6kN, which would be perfect. Also just because it has a longer stroke than 5mm doesn't mean you need to use the full stroke. It would be far easier to implement as well, and programmable once you start with the ATC project.

[handlewanker]

Hi.....just did a few tests to see how much effort is required to unlock the tool.

Attached is a photo of the manual draw bar actuator I made fitted to the top of the power draw bar housing.

The second photo is the plastic brush carrier that melted on the second fail.

The bolt is a 12mm X .7 pitch hex bolt and the spanner is a 150mm long double ended ring spanner......using a small spring balance it took 2Kg to make the spanner move and rotate the bolt the two turns required, so no great effort at all.

That works out to 1KG on a 300mm long lever or approx. 2 foot lbs of torque.

You could probably calculate the pressure exerted by the bolt with those figures, but I think a cam operated design with a geared down motor would not need a large motor to drive it.

A geared motor with an output of approx. 15 rpm would take 4 seconds to rotate once, and as it only needs a half turn to actuate the draw bar a distance of 1.4mm. plus the clearance of another 2mm and that equates to 2 seconds going down to release the tool and another 2 seconds going up to clamp it.

I'll probably use that design as most of the parts are available in one form or another.
Ian.

[tmarks11]

"hand held pneumatic tools"........I don't have any......I do have a compressor but all my power tools for weld clean up etc are electric.....I don't do ANY weld prep either as I weld with a plasma welder.

Well I primarily TIG, which requires clean materials. Hand-held pneumatic tools are much more convenient than electric, as they are quieter, significantly lighter and more powerful, less expensive and last longer in a gritty environment. While I do have some electric angle grinders, I prefer the pneumatic tools.

[jips]

Less expensive but needed a good compressor for pneumatic tool would love to have a infite screw type btw !

Envoyé de mon GT-N7100 en utilisant Tapatalk

[handlewanker]

Well I primarily TIG, which requires clean materials. Hand-held pneumatic tools are much more convenient than electric, as they are quieter, significantly lighter and more powerful, less expensive and last longer in a gritty environment. While I do have some electric angle grinders, I prefer the pneumatic tools.

Hi.......Having used and own all the welding types....Mig, Tig, Stick and Oxy......one day I saw an advert on EBAY for a MULTIPLAZ 3500 plasma welder......after a hands on demo at my local tool supplier I bought an outfit.

That was 4 years ago and I've never used the conventional welding stuff since........there's a video on UTUBE showing it working......pure heat on steroids with 8,000 deg C.
Ian.

[handlewanker]

Hi, just worked out a G code sequence for circular interpolation using I & J instead of R etc.......I managed to create a circle and a second bigger circle simulating a hole with a counterbore, so it's starting to make sense in small doses.........now I can relate to the tool path in Mach 3 and see what the code will generate before the machine is switched on.
Ian.

[handlewanker]

Less expensive but needed a good compressor for pneumatic tool would love to have a infite screw type btw !

Envoyé de mon GT-N7100 en utilisant Tapatalk

Hi, yes a screw type compressor would be nice......but they're a bit expensive and not all too common in the smaller sizes..

When I start to do some cutting and need coolant I'll have to think of some form of air supply for the mist coolant.......just have to work out the amount of air flow and pressure needed etc.
Ian..

[gadgets]

You could easily duplicate the brush carrier from a piece of Phenolic Sheet. It will not burn.