DRO install on a Sieg SX2.7

[glue-itcom]

First part of me installing a Machine-DRO measurement system



This is a good quality kit of parts and brackets

 

[glue-itcom]

Next is the installation of the z-axis and the display



just X and Y to go

 

[glue-itcom]

Finally I have completed the installation of the Machine DRO universal 3 axis kit onto the Sieg SX2.7



Back to the model making

 

[glue-itcom]

After creating a space between the column and the power supply case I decided to make a bracket to increase the stiffness:

The green felt on the edges is to stop the rattling.

This has increased the static stiffness 1.5x

 

[glue-itcom]

A video describing the design and installation of this bracket

 

[glue-itcom]

With this new stiffening bracket the vibration on the mill is dramatically reduced.

Stiff => low vibration => better milling finish

This was an end mill cut with a Milling Cutter Store 6mm carbide 3 flute bit at 1000rpm, no cutting fluid.

 

[clockworkcheval]

Two solutions to reduce vibration that I still use every once in a while. First damping. In the big main machineshop of Philips in Eindhoven when machining a large complex fabrication or fragile casting we placed a few sacks of sand of about 10 kilo each on, in and around the part. It still works for me on my small mills. Second increasing the stiffness. In the early seventies at the Technical University of Delft we experimented with the then new quite thin professional PTFE tape. You put it on the sliding surfaces of beds and carriages. The main intention was to reduce slip - stick for numerical control. We found it did that, but as an unexpected benefit we found that you can also reduce the play in the gibs to about zero thereby greatly increasing the stiffness in the movement while decreasing the required moving force. The caveat is that you need to use the thinnest possible PTFE tape and that you have to take great care by gluing it on. The risk is that the combined effects of oil and chips on the ways will eventually scrape off the tape.

 

[glue-itcom]

Two solutions to reduce vibration that I still use every once in a while. First damping. In the big main machineshop of Philips in Eindhoven when machining a large complex fabrication or fragile casting we placed a few sacks of sand of about 10 kilo each on, in and around the part. It still works for me on my small mills. Second increasing the stiffness. In the early seventies at the Technical University of Delft we experimented with the then new quite thin professional PTFE tape. You put it on the sliding surfaces of beds and carriages. The main intention was to reduce slip - stick for numerical control. We found it did that, but as an unexpected benefit we found that you can also reduce the play in the gibs to about zero thereby greatly increasing the stiffness in the movement while decreasing the required moving force. The caveat is that you need to use the thinnest possible PTFE tape and that you have to take great care by gluing it on. The risk is that the combined effects of oil and chips on the ways will eventually scrape off the tape.

Thanks, might have to make up some small sand bags. Plus I reckon I could fit a sand bag in the space in the lower column.

 

[clockworkcheval]

Excellent idea! You might also try the PTFE tape solution, as your chosen name seems to imply that you will be able to meet the challenge of gluïng it correctly.

 

[glue-itcom]

Excellent idea! You might also try the PTFE tape solution, as your chosen name seems to imply that you will be able to meet the challenge of gluïng it correctly.

I will keep the PTFE tape in mind. Thanks again

 

[Steamchick]

Hi Clockwork cheval... As the only material that can stick to PTFE is burnt egg, (in non-stick pans) can you tell me what glue you used? I guess a rubber contact adhesive, or something that will provide some adhesion to the Steel and PTFE? Or maybe an anaerobic (Loctite?)? I have a can of PTFE spray - I'll try that soonest!
Thanks for the tip!
K2

 

[clockworkcheval]

Hi Clockwork cheval... As the only material that can stick to PTFE is burnt egg, (in non-stick pans) can you tell me what glue you used? I guess a rubber contact adhesive, or something that will provide some adhesion to the Steel and PTFE? Or maybe an anaerobic (Loctite?)? I have a can of PTFE spray - I'll try that soonest!
Thanks for the tip!
K2

It's about 50 years ago. I don't remember. Maybe the then specific brand doesn't even exist any more. But I'm sure that companies like PTFE.eu and holscoteurope.com and many others can assist you and probably have adhesive PTFE tape for machine building purposes in their productline with thicknesses from 0,08 mm up.

 

[glue-itcom]

Just made up some sand bags and placed them in the void in the column:

Thanks to @clockworkcheval for reminding me of the use of sand. We used this before at work when creating an "infinite beam" - essentially you can damp the ends so that vibrational waves get absorbed and don't get reflected.

 

[glue-itcom]

video showing the assembly of the bags into the space

 

[Peter Twissell]

I understand that to glue PTFE there is a chemical treatment which alters the surface of the PTFE to allow glue to adhere to it.

 

[Steamchick]

Hi Glue-it. Seeing the sand-bag damping idea, I wonder if filling the steel column of my Mill-drill with sand will also damp vibrations? It's about 4" diameter, 1/2" wall, so "very stiff" in torsion compared to the box form open steel channel you are dealing with. So maybe my vibrations are at a high higher frequency (lower amplitude) and that's why I have never noticed a problem? Or maybe I don't do such precise milling anyway to realise the problem?
Looking at your back plate, I would have added some horizontal bracing as well (making small boxes), perhaps even welding in some "lids" to make them sealed boxes. Much stiffer in torsion?
K2

 

[glue-itcom]

Hi Glue-it. Seeing the sand-bag damping idea, I wonder if filling the steel column of my Mill-drill with sand will also damp vibrations? It's about 4" diameter, 1/2" wall, so "very stiff" in torsion compared to the box form open steel channel you are dealing with. So maybe my vibrations are at a high higher frequency (lower amplitude) and that's why I have never noticed a problem? Or maybe I don't do such precise milling anyway to realise the problem?
Looking at your back plate, I would have added some horizontal bracing as well (making small boxes), perhaps even welding in some "lids" to make them sealed boxes. Much stiffer in torsion?
K2

If you don't have a problem then I would leave alone. The only data I have so far for it working is that I have noticed a reduction in cutter noise or more correctly I have noticed the belt noise is significant even when making cuts.

I was going to ask a friend to weld it, but just a tad worried it would warp slightly. As you suggest a box section would make it even stiffer.