DRO's

Hi All

I was amazed to see what advanced kit is available affordably for the hobbyist and I am intrigued at the possibilities offered by Digital Readout kit that can be fitted to a Myford ml7. Does anyone have any experience with these, are they reliable? You can get a single y axis for £35 that can read better than half thou for example

The question in my mind is whether they are reliable, Do they lose track or mis count the pulses, are fragile, temperemental (like its owner)? Are these cheap ones just friction wheels on a ruler - liable to slip?

You can also pay £400 for a full blown x y system with remote readout and optical etched strip or a magnetic strip which is better. Can I trust a magnetic strip with my Eclipse DTI?

Cheers

Robin

Robin, may I suggest you type DRO in the search box above, read all and then ask again?

Even a digital caliper for a tenner fitted to your cross slide is reliable and good for 100th of a milimeter

Anything with a battery should be checked every month or two for leakage though

Edited By Ady1 on 30/10/2012 11:13:48

Quite right Kwil

I am just beginning to realise how out of touch I am, never been near a CNC mc. I remember fiddling with a pillar drill with 6 chucks (like a capstan) and actuated pneumatically and run by punch papertape!!!! It was so unreliable that you spent more time setting and adjusting it than doing the job. The guv threw it out.

Digital caliper on the cross slide for £10 . This is a Meldrew moment for me "I do not believe it"

Will do some digging

Cheers

Robin

I am in the process of fitting scales (Glass) to my X3 mill, be aware that the sizes do not fit all aspects and you need to measure the available space very carefully. Particularly the depth of the set up.

At the moment I only have the 'Z' axis fitted as I have had to change a slide because it did not fit the space for the 'X' axis. You may have to dismantle parts of the machine to fit the 'Y' scale.

The display unit is brilliant and works fine on the one scale fitted. Slanting lines of holes, PCD in dia and number of holes and also milling contoured surfaces convex and concave. Measurement down to 5Microns. and even allowance for shrinkage for plastic moulds.

The Lathe fitting is a bit less advanced and as such i think one of these Digital verniers with the scale at rightangles to the scale is better suited for the lathe.

Clive

Clive;

"The Lathe fitting is a bit less advanced and as such i think one of these Digital verniers with the scale at rightangles to the scale is better suited for the lathe."

Hello John, I did consider fitting one to the lathe but as yet have not got around to it, I know that a reading applied will take double the cut but all I would be interested in is repeating the last reading/cut. Maybe already measured with another vernier.

I think ArcEuro do them, users say that they gunge up if cutting fluid is used, but most of us apply it with a brush.

Other than that I cannot answer the question and am sure someone will come along soon with a credible answer.

Clive

Hi Clive

I too am new to DRO. You can pay a lot of beer vouchers for an xy system w remote ro.

I am going to try out a cheap and cheerful scheme

hereto explained

**LINK**

Even expensive systems will have the same contamination problems, so a 10quid vernier seems like a throw away bargain

Cheers

Robin

I did a digital aids thread a while back

Modern stuff is great, I can even screwcut metric threads under constant power on an imperial lathe

I don't use coolant though, just a wee bitty of oil

The caliper has to be lined up very carefully to work properly when it's mounted, otherwise you get a jerky reading

once it's done properly though, it's great

Edited By Ady1 on 30/10/2012 23:59:02

I have spent the most part of last saturday fixing the cheap set of DRO 's i fitted to my mill earlier this year and while the entire set up came in at under $300 i now wish i had spent the extra cash for better quality .

The only problem is my local supplier only supplies Easson brand and to do a 3 axis set up will cost well over a thousand bucks and more if i want the top of the range scales .

The cheaper scales seem to work ok and i used some capping channel for colourbond fencing to make up some covers that keep the oil and swarf away but there are some niggling issues that will drive you nuts eventually .

If they have any sort of USB fittings for cables they will rattle loose and if they are mini USB they are fairly fragile .

I damaged one of the plugs and ended up having to solder the wires directly to the circuit board as i couldn't find a replacement cord that hada male mini usb plug at each end .

This was no fun at all and gave me a great deal of grief as the tracks on the pcb are minute to say the least !

If they are battery powered as mine were you will need to replace them often and i found mine went flat every few weeks even if not used .

So they are now powered by mains adapters and i had to make up a regulator box with 3 separate regulators to supply the 3 different voltages as the x & y units are 3v , the z axis scale is 1.5v and its remote display is 3.7v.

They now work well but the auto power off that is inbuit is annoying and for some reason the z axis scale display is controlled by the power off feature on the z axis scale which turns both of after 2 minutes of idle time .

The problem i face now is getting the display to turn on again with the scale as the scale will re start with any movement of the quill and when both were battery powered i would just switch the readout off and back on to re start it up again and it would read the last stored reading .

The z axis scale has a mini readout like a digital caliper that still works fine- maybe it is something to do with the main display as you could not use it whilst charging the old battery ( mobile phone type with 3 connector pads .

So for now i have a reset button fitted to the regulator box that cuts the power to the entire z axis system which resets something internal in the main diplay and it fires back up ok but now reading zero .so i have to write down each depth of cut for reference or only use the small readout that is on the z scale which fires up with movement - very frustrating !

My main though on this is it could be electrical noise from the power supply causing some issues with the data stream from the scale to the readout or in the readout itself or maybe that middle pad connector on the battery that is not marked with anything actually does something ?

The other 2 are marked + & - and measure as marked .

Ian

You seem to have come to that conclusion very quickly. Take a look at the glass scales and see the rubber seals and the additional extruded covers that fit them. These offer far greater protection than a digital scale just fixed to the machine and with the readout away from the dirt that also stays clean.

If you really want a robust ststem which I assume you mean by expensive then the Spherosyn and Microsyn scales for example can almost be run submerged in suds if you wanted.

Like several others above have said I took the digital scales off my mill as they were just too problematic.

J

I have 2 of the cheap DRO's fitted to my SX3 mill for the past year and have not had any problem with them. But at $70 each I will get a replacement if one fails. Like the $20 digital calipers they do not like getting wet. The only problem that I have had is with the one factory fitted to the Z-axis.

Even though they are not as robust as other DRO's and can only measure to 2 decimal places of a mm, they do make milling a lot easier.

John ,

I have tried this to no avail as the readouts are stable and work well but thanks for the tip anyhow .

I will try running the regulator unit from a battery to see if there is a change and if there is i have a noise problem with the swichmode powerpack.

If not i will try running the scale from its original battery and see what happens then switch over and run the display on its own battery.

If all else fails i will scream at it and threaten it with my largest hammer !

Probably won't do anything but i will feel better!

I followed your link for the DRO's and purchased a 3 axis kit for less than i can buy a display unit from my local supplier !

Thank you !

Now i have to wait for it to turn up so i can get my grubby little fingers on it !

Ian

Hi Ian

Assume you mean this piece of 3 axis milling complete kit for £369 inc pnp sent from uk

**LINK**

Reading the spec it seems amazing what you get

I think I would put the readout unit on a back wall away from possible contamination (especially rear sockets and a bit of cling film over the front. I have asked the site how long the cables are supplied with the scales, will post

The older I get the more I know how litle I know

Robin

I have that very system from that very supplier in Nottingham and it works perfectly.

If you phone Colin Robinson, the proprietor, I'm sure you will find him extremely helpful.

I collected mine from him directly and Colin answered all my questions and also pointed out various alternative options.

Martin.

Well thats a quick response

Hello, Thank you for your interest in our products.

The cable on each scale is 3 meters long. However, we have cable extension in stock in UK. It costs 8 sterling pounds per meter.

Hope I have understood and answered your question.

Regards,

JJ

Impressive, they are ahead of me

Robin

Hi Robin.

Yes you are correct and there were a few vendors on Ebay but i chose that one because everything that was advertised i could see in the pictures including the name of the manufacturer .

Another seller was selling a similar unit but it just had a model number on the front .

After transfering the money across i received an E-mail from JJ very quickly thanking me and asking what scale lengths i needed and another a few hours later to let me know it had been shipped .

Very efficient !

The E-bay feedback on this seller are 100% positive also .

As Martin stated you can get it direct in the UK but here in Australia mine will come direct from china so if you can pick it up yourself that will save you some cash .

Ian

Ok after what seemed like an eternity of playing around ( and no i'm not an electronics technician or engineer ) i have i supposed fluked upon the solution for the Z axis problem with my DRO as mentioned before in this thread .

I found i could get it to work with the original battery in the scale unit but if i tried to run the lot from a SLA battery via the power unit i had constructed it still would not work .

So not a noise problem but maybe a voltage sensing issue and without a schematic or any idea what hides underneath the little black lumps on the circuit board there is little one could do .

Anyhow after a few beers i was fumbling around and happened to touch the pads with my finger of some SMD capacitors mounted next to a large black lump i believe to be the main controller for the display and it shot into life !

It seems that one of the four capacitors next to the controller ( all104k ) has something to do with reseting the display and as this terminal is connected to the positive rail via one of the capacitors my touching this must have created a - voltage or maybe a logic low to this terminal of the controller .

So a 10uf electrolytic capacitor was soldered to the + supply and to the low or (-) side of this SMD capacitor and the original reset button was pressed into service to to creat a new reset button by connecting the power momentaritly to this display .

So now if the display shuts down to power save mode and i just feed the quill downfeed then press the red button and all of the stored info is there as it should be .

JOY !

Ian

Edited By SLOTDRILLER on 02/11/2012 08:41:52

I am one of those satisfied customers John mentions. I did my SX3 Mill and the transformation was unbelievable. I've just done my lathe and its a different machine. I can now concentrate making things accurately rather than trying to remember where I am with my counting. The built in functions move the machines to another dimension.

Pete

I think I am going to buy myself a Xmas present when I finish installing my Dore Westbury