[joeavaerage]

Hi,
I have devised a way to rapidly tram the vice.

At the moment I have no Home switches and given that they need to be repeatable to 20 arc seconds or better, its going to take some time to design and implement.

In the mean time I made this acetal block that keys into the vice and that has Ohmic contacts. Now I can use just a two wire probe circuit and I can tram the vice in under a minute, and that
is both directions, the A and C axes.

I will write a short macro to automate this, and have it as a button onscreen. Thus to tram the vice, load the block, attach the probe wires, jog to an approx preposition and hit the button,
and voila, the vice is trammed. I think if I use the 'Home in Place' function, this routine would reference the A and C axes. This would Home the A and C axes until I fit proper Home switches.
You know the saying about 'there is nothing so permanent as a temporary solution', I wonder if this might be one of them!

Craig

[peteeng]

Hi all - Interesting mechanism -Peter

[joeavaerage]

Hi peteeng,
is there any advantage of these over a hexapod?

Both of these units require at least one hinged arm that is torsionally stiff, whereas a hexapod requires six axially stiff arms that are not subjected to torsion at all.

Craig

[peteeng]

Hi Craig - I think the interest is that the kinematics are easy to calculate. The XYZ position is the XYZ position of the car, same a a cartesian machine. Plus its less mass to move but less mass "could" mean less stiffness. It also has lots of connections which means loss of accuracy. Just for interest... Peter

To answer your Q. They take up less space then a hexapod vs the working envelope and they seem to be able to rotate further.

[joeavaerage]

Hi,
the hexapod style is quite common on Pick-and-Place machines, where very high speeds and accelerations are required. I have seen speeds advertised of 100m/s!!!
Given that computing power has become so cheap I would not expect the kinematics calculation to be such a big thing. I would however guess that any machine that can do 100m/s could and would have accelerations
of 10g or more and thus stiffness is still as important as any CNC machine.

Anyway, as you say, an interesting two machines.

Craig

[peteeng]

Hi all - I'm updating Fusion with the advanced simulation extension . Hopefully to do lots of generative design on the next machine. Time to start Milli again in review of all the info amassed here. Peter

[joeavaerage]

Hi peteeng,
I am familiar with Fusion Machining Extensions but not Simulation Extensions.

What extra features do they add that you want or require? Even the fact that you are considering paying for Simulation Extensions suggests that you are happy with the existing Simulation stuff.
How does it compare (price vs performance) to other software you have used?

Autodesk is very generous with deals for first time buyers of their extension packages. Is it polite to ask how much you paid?

Craig

[peteeng]

Hi all - I'm updating Fusion with the advanced simulation extension . Hopefully to do lots of generative design on the next machine. Time to start Milli again in review of all the info amassed here. Peter

[peteeng]

Hi all - Small 5 axis machines - Peter

[peteeng]

Hi Craig - The prices are as per the list on their site. I'm going to run the simulation extension for a month to see how it goes. This costs <$300 for the month from memory. The features can be used monthly so I can cost that cost into quotes as needed vs having to pay high annual subs for software that may be stagnant for long periods. What they do is hold the current price for your subscription for say 2 years if you pay up now or before the next price hike.

Seems cnczone has fixed a few things I have a flood of updates from threads...

So the basic simulation is static stress analysis, modal and its shape optimisation is a preview function and you can't get at weights and various things.... The extension gives you access to the full generative design stuff, It also has buckling which I need and advanced bolt analysis which I need. Simsolid basic does not have buckling. Bolts are non linear when preloaded and then you place more service loads on them. I do bolt fatigue analysis and currently have to run two static models then do hand calcs to get the fatigue stuff out of simsolid basic. Perhaps F360 ext will do this for me. So the ext for me is buckling, large deflection, floating structures (I do stuff for barges and marina work and floating structures you can't do in static analysis, if I have to float a structure I use Strand7 but its really clunky old fashioned to use) and if F360 simulation does what simsolid does then its much cheaper per year then simsolid basic, say <$3000 vs $13000. But F360 solves slower since its meshed. Since a company pays for simsolid that's fine but they may choose to not pay sometime in the future...

I want to use genDesign in the next MIlli round.... I've been reading the Milli thread and it breaks down to machine configurations and materials. I keep coming back to the Mori M2 and solid aluminium (or laminated) or solid steel....Peter

[joeavaerage]

Hi peteeng,
Autodesk strive for new customers.

As you know I have Fusion Machining extensions. The list price is $1600USD/year. As an introductory offer they gave me a year subscription for $1200USD. By the time it was converted to NZD and included
GST it cost $2250NZD. That was about 16 months ago. When the time came to renew the subscription I was no really in a financial position to renew, certainly at the list price. I too considered either monthly,
weekly or even daily use, but the effective cost is high doing it that way.....but beggars can't be choosers either. Autodesk offered a very good deal for me to renew the subscription, $1900NZD + GST
or $2185NZD which I accepted and paid. This is a very substantial discount off the list price. What surprised me also was that the Autodesk rep seemed largely to ignore the USD list and instead worked from the NZ/Australia price
list, which seem rather more generous.

All-in-all if you find you like Fusion Simulation Extensions talk to an Autodesk rep, you might be surprised how deep a discount they will offer up to get an annual subscription.

I've been reading the Milli thread and it breaks down to machine configurations and materials. I keep coming back to the Mori M2 and solid aluminium (or laminated) or solid steel...

My own estimation is that I am configuration agnostic. Any, at least of the commonly adopted solutions, can be made as stiff as any other. One arrangement may suit a style of construction, or may offer
less swarf contamination, or a larger envelop....but no one arrangement is that advantageous that is precludes consideration of other arrangements.

I preferred a column design as it offered the best design flexibility both in current form but also for future developments, a trunnion fifth axis for example. Particularly the idea that I would have what amounts to
modular axes in the form of cast iron axis beds favored a simple column type frame to which to bolt them.

I have always been a fan of traditional materials like cast iron and steel. Steel offers about the most stiffness for a given sum of money.......and if you had a complete engineering workshop it would be an easy
choice. Most hobbyists do not have that sort of facility and shy away from steel/cast iron on the basis of perceived difficulty and cost, and try other less traditional materials like EG and UHPC and granite.
Each of those materials bring their own challenges and none have to date seemed that advantageous that precludes consideration of the alternatives.

Craig

[joeavaerage]

Hi peteeng,
have you ever considered unitized axes?

Imagine building three axes beds replete with ballscrew, linear rails and saddle, but all three identical? If you chose UHPC then just one mold and a simple one at that.
Three beds, say 500 x200 x100, would be an easy proposition for machining the rail beds flat.

You can stack one atop another for a traditional X-Y axis combination , or have one on the base of the machine, with a second as a gantry, with the third mounted atop the second
for a fixed gantry/moving table design. basically a fixed frame that hold all three axis bed mutually orthogonal....gives choice?

Craig

[peteeng]

Hi Craig - I have looked at that in the past. Although they are replete (visions of grapes and togas) within themselves once you get to the machine it becomes another layer to deal with. I think its better to design each machine component for its own end vs trying to generalise the design. Every time you generalise something this is a compromise. You can buy unitised drives like attached from various companies but they do cost quite a lot compared to separate bits. Comes down to what the Maker wants to do. Since all of my machines are designed for serial production in theory I don't see the value in such a general solution better off optimising the design as far as possible. If the product then sells, the volume sorts out the rest. I choose the best solution within the budget and have access to big machines if I need surfaces trued so I'm not in a corner like some. Peter

PS its sort of what I do with the timber beds. See attached scoot image. I now have a source for harmonic drives and slew bearings so Epoch5 needs to be detailed out.... Peter

[joeavaerage]

Hi peteeng,

I think its better to design each machine component for its own end vs trying to generalise the design. Every time you generalise something this is a compromise.

I'm not sure I agree. I designed my axis beds with 'no compromises', but to reduce the cost that is when I decided to make them all identical. One pattern....but three castings.
The only difference in the machining between the three axis beds was that the X axis had T slots milled into it. This again saved money....and therefore I was able to afford
a 'no compromise' design, whereas if each axis were individualised it would have cost considerably more OR I accept would have been forced to compromise to meet a realistic budget.
Not to say that making three identical axis beds with a 'no compromise' design was cheap, but it would have cost a damn sight more had I done it any other way.

I'm sure you can imagine also that three identical axis beds bolted to a large 'L' shaped steel frame resulting in a column type machine is a great, easy, 'no compromise' way to
employ the three beds. They are sort of an ideal match. If however I decide at some later time to change the arrangement then I can unbolt the axis beds and mount them in some new
frame. Most importantly I am able to retain the three axis beds, because they cost a fortune. $10,000NZD for the casting, stress relief and machining. Then add to that the linear rails,
the C5 double nut ballscrews and three 750W servos, one braked, so I spent something like $15000 (total) on these three axis beds. I doubt I will ever make another axis bed again,
they have another twenty years life in them which will probably see me out.
Craig

[peteeng]

Hi Craig - Everyone's best design and best set of compromises is different and leads to their own "best outcome". But the grail is out there... Peter

[peteeng]

Hi all - I have been working on a 5 axis router called Epoch5. I'm tossing up between a steel trunnion and an aluminium one. The AL one would be cast. I have a favourable quote at $30AUD/kg from the caster (included heat treat to T6 which I prefer). So now I have to detail out the two concepts and cost them out for a good decision to be made. I do want to get involved in aluminium casting as I see it as the way forward... Today I did a quick FE on a 35mm slab of AL vs the 50mm deep 12mm thick steel version (both 200mm wide). F360 materials went really weird today so I sent a strong note to autodesk that the way materials are handled in F360 is the worst way I have encountered in any CAD or FE system ever. So the AL 35mm thick weighs 11kg and the steel weighs 15kg so AL wins there so we shall have to wait for the costing to decide... They deflect nearly the same in a plunging load case. Peter

[joeavaerage]

Hi peteeng,
the base of my trunnion is 32mm thick steel. It was plasma cut then placed in a machine to buzz around the edges....but no heat treatment or any messing around. The 32mm thickness allowed me to bolt the
20mm uprights on and use plenty of torque on the bolts to ensure that the upright remained square. The greater the thickness of the bottom plate the less deflection might be expected from the uprights.

Cost $122NZD +GST and weighs 20kg. Cost me a box of beer to have the edges milled square and true, my own machine is not big enough or rigid enough.

Quite frankly by the time you bend a piece of 12mm plate with a return on each edge it will cost more than just a single piece of 32mm (or 40mm or 50mm...)....just to save a few kg????

Second issue is that you have shown the stepper/servo of the fifth axis concentric and parallel to the fifth axis bearing. That will make you fifth axis very tall and consequently the walls of your machine will need to
be very tall also, counting against stiffness. You need to minimize the height of the fifth axis stepper/servo, gear reducer whatever it is and the bearing stack. This in turn suggests you need a right angle drive
so that the stepper/servo be parallel with the underside of the trunnion table.

Last thing I would comment that I would design the fifth axis such that the platter is below the centerline of trunnion even if only by a few mm. If you have a control that you know is capable of TCP then maybe you don't care......but if you
don't then the center point of the machine, ie the intersection of the A axis (trunnion) and C axis (fifth axis platter) be exposed that you might touch off to it. You will absolutely need it to set up the stock to be machined.

Craig

[peteeng]

Hi Craig - point by point
1) This is a prototype router not a mill. For plastics, timber maybe aluminium. So stiffness requirement is not near a mill
2) I want to avoid a flat plate and bolted flanges. So bending allows a couple of things that "flats" don't
3) I looked at right angle drives and they are very expensive (low lash units) plus did not save much height. Agreed trying to minimise machine height is important... One design V12 has the trunnion low with a fwd gutter for the motor to swing thru. We shall see how V14 goes now I have settled out the trunnion options. Harmonic drives are very flat but very $$$ and I'm unclear how some of them anchor. Waiting for more details about those from the supplier.
4) I have not looked at the stack height of the system yet, been struggling with getting the trunnion concept right. I think a laminated steel bent design will be fine. My Z axis costs around $75aud to be laser cut and bent and it has proved to be very stiff. Its 3mm steel laminated to 6mm or 9mm. In the trunnions case I think 3 layers is good. But the top would be a very big dust/swarf collector so I'm thinking an upward flange is not a good thing. But the direction is clear and I'll detail an AL version to see cost deltas.
5) Getting the geometric relationships correct is now the big effort... I shall have to start reading up on F360 posts to see what its capabilities are.. Peter

I looked at bent thick Steel and aluminium plate, cast concrete, fibreglass/carbonfibre, steamed laminated ply and eventually cast aluminium came out where I wanted it but then laminated steel came back up... Once my mind had settled down to a reasonable level of activity and direction

edit - I tracked down the Z axis thickness calc. My Series3 laminated I section from 3mm steel is equivalent to 32mm of solid steel in bending or 46mm of aluminium so its light and stiff... My series 2 was made from 6mm steel and it was equivalent to 40mm thick of steel its flange depth was 55mm but it cost quite a bit more due to paint and or made from stainless. This one will have zinc plated parts so steel thickness is not that critical..

[joeavaerage]

Hi,

I shall have to start reading up on F360 posts to see what its capabilities are.

Its not the capabilities of Fusion that need concern you but your motion control. Fusion can produce either plain vanilla five axis Gcode without TCP, OR can produce Gcode which
is then interpreted by a TCP capable motion controller. It is the motion controller that calculates the required kinematics for TCP. This separates the 'men from the boys'. Most hobby CNC
solutions do not have TCP kinematics. The notable exception is LinuxCNC, but even LinuxCNC aficionados do admit that it is not that easy, but certainly possible.

You can see from the attached pics that in order to reduce the height or equivalently the max swing radius of the trunnion I used a right angle gear reducer but elected to drive it by
a belt that allowed me to place the servo alongside the gear reducer and minimize the swing radius as best I could. Of course there are even better solutions but the costs just spiral out of control.

I would suggest to give yourself and any potential customers of yours the ability to use this machine WITHOUT the benefit of TCP. Should you or they have a TCP controller then that is great,
but the machine should still be useable without TCP. For that purpose having the centre point of the machine a few mm above the platter is advantageous.

Craig

[joeavaerage]

Hi peteeng,
I did briefly consider casting the trunnion, but in cast iron rather than aluminum. What put me off was not so much the casting itself but rather the machining afterwards. It would in effect require a five axis machine to do
in one setup OR at least a four axis horizontal. As my trunnion table is 370mm long that restricted the possible machining facilities to the very best in the city and the most expensive.

I decided to fabricate the trunnion with one reasonably thick base and uprights bolted to it. To date I'm very happy with it. Any compliance I've noted in the is not in the uprights as I thought it might.

Craig