Highly sought-after Aciera F1 and Sixis mini-mill

[Steve WanParticipant @stevewan33894]

Hi guys

 

Wishing the owners of these fine Swiss made precision mini-mill to share some light over the amazing design of the spring compensator that is built in the vertical column to overcome the upwards feed weight of the mill table and machine job. Also how to tension these springs and their work sequences.

 

I could not source any findings in the net.

A very good design that other mill machines should follow with upward

feed motion.

 

I hear from you guys

 

 

[Steve WanParticipant @stevewan33894]

Design of internal spiral spring suspension

[Billy MillsParticipant @billymills]

Hi Steve,

You can find a F1 manual at :-http://dl.free.fr/updbry0WB  . This is a 140M pdf so not for slow connections. The compensator is  described between p26-30 under ” compensation de la coulisse verticale”. Although Aceira manuals are always French German and English the English text has been removed- well it is a French site.

 

Like everything else Aceira the compensator is very simple, a spring, drum and wire rope inside the machine. The F1 is a very small mill for miniature work on  watch or instrument parts so the feed forces are very small. The F1 has the built in  option of using levers as “sensitive feeds” so the table mass can be partially compensated to reduce the apparent force needed on the levers.

 

On a larger mill this arrangement would be unworkable, the mass of the table of an F3 – or any other medium sized mill with a  moving table- is huge compaired with the F1.  The mass increases as the cube of the linear dimensions so a tripled table weighs 27 times more.

 

 The vertical leadscrew on the F3 works just fine as it is, there is NO backlash with the table mass pre-load and it is easy to wind the table up and down.

 

regards,

Alan.

[John HaineParticipant @johnhaine32865]

An alternative is a Spiroflex extension spring –

http://www.spiroflex.com/extensionsprings.html

 

These are used in things like modern sash windows and for closing sliding vehicle doors.  I have yet to get the company to reply to my enquiry!  

 

I used to own an F1 which I inherited from my father (he bought it from his company when they closed down – they made electron microscopes), with quite a lot of accessories.  Beautiful machine (though leadscrews very worn), but much too small for model engineering.  I got a good price for it and bought a Myford mill.

 

John.

[Steve WanParticipant @stevewan33894]

Hi Alan and John

 

Appreciate your useful info. also the source of supply.

I was able to download the English version of Aciera F1 manual.

 

But I still puzzled how the spring drum and wire work?

Any diagram to refer to? Especially the way it’s tension? Why

the F1 mill table has to be at the lowest position not higher?

 

I stumbled across another similar principle, Record Morticer WRM 200.

It uses a compression spring and attached to a chain that winds round

a gear. So any downwards pressure (slot drilling) will be assisted by

upward movement after drilling…anyone knows about Record Morticer WRM 200??

 

Steve

[John HaineParticipant @johnhaine32865]

If tensioned at highest position to balance weight, will be over-compensated at lower position, maybe likely to make mill more likely to snatch when plunging a drill or mill?

 

[Billy MillsParticipant @billymills]

The F1 is a very small mill, it is intended for watch and instrument work and will often be used with magnifiers or a sterio microscope. So the levers are a good way to operate the slides whilst looking at the workpiece.  If the table is used with stops and jigs then small batch production of very small parts becomes easy.

 

The vertical motion can be compensated to ease the load on the vertical lever. It is as simple as that. The compensator is like a large clock spring in a drum, the wire rope is on the outside of the drum so the rotation of the hellical spring is smal so the rope tension is fairly constant an set to partially cancel the mass of the table and slide ( which is VERY heavy) 

 

I think that the real design lesson is not the compensator but the whole machine and it’s milling performance. The Aceira’s /Deckel/ other euro mills leave everything else in the shade due to the exceptional stiffness of the design, that is why they are so sought after.

Lates.co.uk has good articles on Aciera and Deckel mills.

Regards,

Alan.

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