Installing a magnetic DRO on my VM32L

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Installing a magnetic DRO on my VM32L

This topic has 29 replies, 10 voices, and was last updated 5 July 2020 at 19:16 by Iain Downs.

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29 June 2020 at 08:36 #482845
Iain Downs
Participant
@iaindowns78295
Hi, experts! I need your help.

I've just taken delivery of a factory DRO kit for my Amadeal VM32L (think WM18 roughly). This has taken 6 months to get to me (I had a choice of a MT3 machine with DRO or an R8 with a factory kit coming later) due to Covid.

All the bits appear to be there, but there is not one line of instruction (other than for the display box).

So far my requests for instructions to Amadeal have not produced any results. I've pestered them again today, but I thought I would try the assembled knowledge here.

Here are the bits.

and a close up of the magnetic tape.

So I guess I peel of the backing tape and stick it to the mill. Is the steel cover just for transport or should it stay on?

The (badly made) brackets don't indicate which axis they are for. I can guess, I think, but I'm not comfortable doing so.

What;s the gap between the reader and the tape? Should I shield the tape when it's stuck on? Most installations seem to do so , but from what I can remember of seeing one in the warehouse in December, they're left exposed.

I'm hopeful I'll hear something from Amadeal, but if there's any advice you can give I would appreciate it.

Iain
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29 June 2020 at 08:36 #15284
Iain Downs
Participant
@iaindowns78295
Where to start?
29 June 2020 at 09:06 #482853
Journeyman
Participant
@journeyman
I would have expected more aluminium in the kit! All the DRO's I have seen have aluminium carrier strips and covers and the magnetic strip is stuck onto an aluminium extrusion and not directly to the machine. This allows for fine tuning the alignment between the strip and the moving read head. I hasten to say that I have not got a DRO on my mill but have spent ages looking at shows and on-line working up to getting one.

John
29 June 2020 at 09:08 #482855
Jed Martens
Participant
@jedmartens56976
There is a DIY Magnetic DRO thread that shows a number of approaches to mounting the tape

**LINK**

In my case, I made an aluminium carrier, while others have attached the tape directly to the machine with good results.
29 June 2020 at 09:59 #482863
ChrisB
Participant
@chrisb35596
The installation kit you have there is very basic, not even carriers for the strip and readheads!

I built my DRO from scratch as described in the link above by Jed. The magnetic strips have adhesive backing and I stuck mine directly to the machine. I drilled no holes for the mounting brackets – either used existing holes or epoxied the brackets to the mill itself (but you could drill if you wanted of course) I think you would be better off to manufacture your own bracketry or modify what you have. You don't have much to work with tbh!

Chris
29 June 2020 at 11:13 #482871
Mike Crossfield
Participant
@mikecrossfield92481
As other have said, it's common to have extruded aluminium carriers for the magnetic strips, which ensure a flat surface and offer some protection for the strip. Also wise to have covers to keep swarf away from the strip/read head. Adjustable brackets for the read heads make it much easier to align the read heads and set the required clearance from the strip. My kit from Machine DRO had the strip carriers and the covers, but the read head brackets were useless for my mill and I had to make my own. I think this is fairly common. The DRO-PROS.COM website has loads of useful information about installation, and several very good videos. Well worth a look.

Mike
29 June 2020 at 15:41 #482923
Iain Downs
Participant
@iaindowns78295
I believe that the factory installation has the strip directly on the machine.

Happily, Jorge of Amadeal has responded to my last prompt but only in so far as he's sent of a request to Weiss.

Thanks for the link to ChrisB's post – and thanks for the post, Chris! That's useful to know.

One thing I'm not clear on is if the steel strip in the photo above is just for protection in transit, or if it should be attached to the magnetic strip in operation.

Another question is if it matters which way round the strip is mounted – left to right or right to left, or if you can set this in the display box.

Iain
29 June 2020 at 15:56 #482924
ChrisB
Participant
@chrisb35596
It should not matter which direction the strip is installed. The stainless strip is a protective cover, and it should have a self adhesive backing. You can use the magnetic strip with or without the protective strip but for obvious reasons I would install it as well once you have it.

Be careful how to install both strips, they have to be installed accurately inline to each other and to the read head.

The way I would go round the installation, if you are installing the magnetic tape directly to the mill is to first get your brackets ready and install them then machine a block of aluminium with similar dimensions to your read head. On the block machine a slot the width of the read tape (as a guide) Then pass the tape through the dummy read head while traversing the axis you're installing the magnetic tape to.

It probably sounds a bit complicated, if you read through my build thread there are photos of how I did it. Probably there are other ways, but that is how I did it.
29 June 2020 at 15:57 #482925
John Haine
Participant
@johnhaine32865
There should be a thin stainless steel strip between the magnetic encoder strip and the read head to protect the former. In the MDRO kits there are slots in the extrusion supplied to fit the encoder to the machine to take the steel strip. Absent that I guess you could stick the strip to the encoder with double-sided but seems a bit of a kluge.
29 June 2020 at 16:51 #482936
Cornish Jack
Participant
@cornishjack
Just finished a fitting on my mill. Slightly more complete bits but instructions needed a magnifying glass and deep searching to find the right reference. Your question about read head clearance – my instructions suggest between 0.1 and 0.9 mm, so reasonable latitude. Most of our members seem to find it quite straightforward – my skill set meant much head scratching!!

rgds

Bill
29 June 2020 at 20:02 #482978
Michael Briggs
Participant
@michaelbriggs82422
I purchased my magnetic scales from Mdro about 6 years ago. The stainless steel strip was not self adhesive, the alloy section was supplied with a round rubber seal similar to o ring material. The final part of installation was to fit the stainless strip and seal it top and bottom with the rubber insert, I finished the assembly by sealing the ends of the scale with silicone.
29 June 2020 at 20:31 #482984
Ian P
Participant
@ianp
Posted by Michael Briggs on 29/06/2020 20:02:00:

I purchased my magnetic scales from Mdro about 6 years ago. The stainless steel strip was not self adhesive, the alloy section was supplied with a round rubber seal similar to o ring material. The final part of installation was to fit the stainless strip and seal it top and bottom with the rubber insert, I finished the assembly by sealing the ends of the scale with silicone.

Mine was the same, the extrusion. magnetic strip and the SS cover strip were all supplied loose. I did fit it all as the thickness of the extrusion only added 10mm to the tailstock side of the crosslide. (Harrison M250) If I had to do it again I would investigate gluing the bare magnetic strip under the cross slide.

The sensor head and its cable (of the Amadeal kit) looks to be a bit vulnerable, I'm not a fan of the spiral metal conduit but its more robust than what is shown in the top pictures, Maybe I'm doing it a misjustice if it has a tough polyurethane jacket.

Out of interest, how much did that kit cost?

Ian P
29 June 2020 at 20:38 #482985
Iain Downs
Participant
@iaindowns78295
Well, I agreed to pay the difference between the Non-DRO and DRO version which is £400. Having said that they appear to have forgotten to charge me and I will not remind them until I have got it all working.

It appears to be a 5 micron set up which is more than enough for my work.

Iain
30 June 2020 at 07:01 #483037
JasonB
Moderator
@jasonb
Looks like they put the X-axis one into the slot at the front of the table where the "tape measure" strip goes on the non DRO machines. Not sure if it is machined out to a different size at the factory.

Y axis just stuck on the side

Edited By JasonB on 30/06/2020 07:41:05
30 June 2020 at 08:10 #483052
Iain Downs
Participant
@iaindowns78295
HI, Jason. That makes sense with the shape of one of the mounts. I will look into that. Can I ask you where you got the photos. I couldn't see them (or the VM32l) on either Amadeal or Weiss web site.

Iain
30 June 2020 at 08:28 #483055
JasonB
Moderator
@jasonb
DRO Pros in the states sell the Weiss stuff, photos are bigger there

Precison Mattews is another seller but not showing anything with DRO
30 June 2020 at 12:00 #483122
Iain Downs
Participant
@iaindowns78295
Thanks, Jason.

Iain
30 June 2020 at 14:46 #483155
Iain Downs
Participant
@iaindowns78295
What is slight scary is that it looks like they've sawn the top of that sensor in order to fit it in!

Iain
1 July 2020 at 09:59 #483259
Iain Downs
Participant
@iaindowns78295
It looks like the groove for the ruler is a good place to put the magnetic strip – short of actually trying it. Also, It seems I have two strips. A magnetic strip with a sticky back and a steel strip with a sticky back, so installing the strips looks fairly straightforward.

There is 1.8 metres of strip (each type!) which is plenty and more to cover the range.

Less pleasing is that it's still unclear how the mounts are meant to work. The one which most looks like an X mount simply won't fit.

I will try taking the ruler out and try fitting the strips, but I'm guessing I will have to make new mounts. Which is annoying.

Iain
1 July 2020 at 18:13 #483345
Iain Downs
Participant
@iaindowns78295
Here are the instructions / photos provided by Weiss. First, I should say that I appreciate that someone took the time to take the pictures.

I'm not entirely sure I need to replicate all the swarf ridden bits of metal round it and I hope I can manage better alignment.

I have to say that I wouldn't call what I've received a kit. The brackets don't fit the sensors and the bar in the picture above is simply not there!

Having said that, I'm now fairly clear on what I need to do to put it all together, though I will need to make my own hardware I think…

Iain
1 July 2020 at 19:35 #483366
Ian P
Participant
@ianp
I'm sure you will make a better job of it than the factory have done!

There appears to be bits of old magnets used as temporary clamps holding the self adhesive(? ) strips in place, I also see the wonky looking sensor on the Y axis (has the casting a machined surface where the strip is located?). If the surface is not machined then there is a good case for fitting the strip in some extrusion. I think I would use some ali 'U' section (with the U upside down) so that the magnetic strip faces downward and the bulk of the sensor head is within the U, as in under an umbella.

Whilst the strip and sensors are probably coolant proof, oil and coolant could migrate its way into the adhesive allowing the strip to detach eventually.

Ian P
1 July 2020 at 20:24 #483375
JasonB
Moderator
@jasonb
I would be tempted to make the X axis mounting bracket "t" shaped as viewed from the front which should allow the two vertical holes that the existing table stop screws into rather than tap another pair of holes. Or it could be a wider block but with two vertical holes.
1 July 2020 at 20:56 #483387
Iain Downs
Participant
@iaindowns78295
Jason. I agree. Also I'm near the end of my Motor Feed build and was planning to use the central position pointer to locate the optical sensor for my end stops – with the stops themselves holding a blade to interrupt the sensor.

Ian. Quite disturbing, really, I'm not quite sure what you mean by U channel on the Y axis. The strip is on the base on the sensor on the saddle so I can't see how to use a U there.

I'm going to have buy some stock to make the various brackets. I've get everything but what I need…

Iain
1 July 2020 at 21:42 #483395
Ian P
Participant
@ianp
I will take a picture so I can post a sketch of what I was suggesting (probably in the morning).

I am not familiar with your machine but if I interpret what I see in the pictures I think their installation has the Y axis strip on the stationary base of the mill, and the sensor head as the moving part. Since the cable does not look particularly robust I would reverse the tape and sensor positions.

Their X axis sensor and cable also look to be vulnerable. There is no need to have the sensor dead in the middle, moving nearer to one end might allow much better routing of the cable.

Drilling and tapping holes in a machine (brand new or old ) would never bother me but I know some people are reluctant (to even paranoid) about making any modifications to a machine, In this case, unless you want to glue everything together, some holes are inevitable.

Ian P
1 July 2020 at 22:43 #483416
Iain Downs
Participant
@iaindowns78295
Ian – I get what you mean about the Y axis, but I think the travel may be greater than the depth of the saddle. I'll measure up tomorrow.

I'm cool with drilling holes!

Iain
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