[peteeng]

Hi Sus - Put files into a zip file that's what a zip is for!! . Changing the extension can corrupt the file. I'll have a look. Peter

[suspension]

Hi Sus - Put files into a zip file that's what a zip is for!! . Changing the extension can corrupt the file. I'll have a look. Peter

Hi Pete,
Please see zipped file.
Thanks
Sus

[peteeng]

Hi Sus - The model looks OK. I set up a point probe on the tool. The tool runs at X147 Y95 and Z93 microns for the 80mm shell model with 10,000N applied. I'm not sure where you are measuring the deflection. If you are just looking at the max deflection, then that point can move around eg the column and ram move much further. The only deflection your interested in is the tool deflection. Use a point probe and look at these so each one is the same....

10,000N or 1000kgf is way too much for the model load. Use 1000N or 100kgf much more realistic. You'll never apply 100kgf to the tool under cutting loads.... Then your stresses will be 10x less....Peter

10000/93=107N/um very stiff

[joeavaerage]

Hi Sus,
this model looks OK. As peter says, 107N/um is very stiff. If you were to actually build the machine you'd probably not do nearly as well, but might get to 50N/um, which would be very creditable
and in line with your target.

Now you could start by looking at each component and detailing it with a view to building it. Now you know the stiffness the machine has to be overall now you can focus on individual parts.

Craig

[peteeng]

Hi Sus - I notice that your rails are on "air" they need to be on webs. When they are made like designed the top plate of the foot acts like a diaphragm or membrane and deflects. It also vibrates. The rails need to sit on webs to remove this deflection. This is a local shear deflection issue. All deflections add up... Peter

[peteeng]

But the rub is many of the parts are made from material that is 1300GPa stiffness. So these need to be corrected to real values before the Toyota jump can be had. Peter

[suspension]

Hi Sus - The model looks OK. I set up a point probe on the tool. The tool runs at X147 Y95 and Z93 microns for the 80mm shell model with 10,000N applied. I'm not sure where you are measuring the deflection. If you are just looking at the max deflection, then that point can move around eg the column and ram move much further. The only deflection your interested in is the tool deflection. Use a point probe and look at these so each one is the same....

10,000N or 1000kgf is way too much for the model load. Use 1000N or 100kgf much more realistic. You'll never apply 100kgf to the tool under cutting loads.... Then your stresses will be 10x less....Peter

10000/93=107N/um very stiff

Hi Pete, I am using a point probe, never used the min max. Did you try changing the shell thickness?

[peteeng]

No didn't change model - The rest is up to you. Change the part stiffness to more real numbers (eg the cars to aluminium and the saddle to whatever your going to use vs the 1300GPa material) and start getting the details figured out. Bolt access, actual part geometries etc... Peter

[suspension]

No didn't change model - The rest is up to you. Change the part stiffness to more real numbers (eg the cars to aluminium and the saddle to whatever your going to use vs the 1300GPa material) and start getting the
details figured out. Bolt access, actual part geometries etc... Peter

I asked it because simulations were giving me wired values which are not intuitive when I change the shell thickness.
I have set most of the other parts except the column/base to un-deflecting (with 1300YM) to try to finalize the casting material.

[suspension]

Hi Sus - I notice that your rails are on "air" they need to be on webs. When they are made like designed the top plate of the foot acts like a diaphragm or membrane and deflects. It also vibrates. The rails need to sit on webs to remove this deflection. This is a local shear deflection issue. All deflections add up... Peter

Thanks, I will fix this. I noticed this but wasn't sure what was going on.

[suspension]

I asked it because simulations were giving me wired values which are not intuitive when I change the shell thickness.
I have set most of the other parts except the column/base to un-deflecting (with 1300YM) to try to finalize the casting material.

Looks like I have done a stupid thingy. when copying stiffness values, I must have copied deflection values for some thicknesses it seems. I redid the simulations and the results are intuitive - The higher the thickness, higher the stiffness in all directions.

Still I am not ready to detail out it however. Even with 80mm thickness, the required Sika 3350 (or Fosroc® Conbextra® TA which has similar properties and is available locally) is too much. My local supplier quoted 64USD per 35Kg bag for 3350!

[peteeng]

Hi Sus - As I have said before. The shape of the parts are not material dependent. Once you find the cheapest stiffest material then its a case of going with it. This does not change how you are going to arrange pocket holes for cars or feet for bolts, webs for external stiffness, metal inserts and various other features. These will take some time to sort out... Do the detailing in parallel to researching the material... you will get it done by Xmas then. Otherwise maybe next Easter you will have a GA. Peter

[pippin88]

Sika3350 is expensive stuff.

For parts that don't move, and where weight does not matter that much, you can use lower modulus material.
Your base and column are not space constrained. Just make them fat. Don't bother with hollows.

Use high modulus materials for where space is an issue - e.g. saddles (you don't want a 500mm thick saddle...)

[Mr-MaW]

Hi Pete,
Please see zipped file.
Thanks
Sus

Sorry, I can't open this file, can I convert the format? （step、xt、igs ）
We look forward to sending you the drawings to my email and I will be happy to help you analyze them.

[email protected]

[ardenum2]

My local supplier quoted 64USD per 35Kg bag for 3350!

Sika3350 is expensive stuff.

that is cheap, $1.85/kg, durcrete e45 comes to about $3/kg, epument starts at $5/kg, cast iron starts at $3/kg.

[suspension]

Hi Sus - As I have said before. The shape of the parts are not material dependent. Once you find the cheapest stiffest material then its a case of going with it. This does not change how you are going to arrange pocket holes for cars or feet for bolts, webs for external stiffness, metal inserts and various other features. These will take some time to sort out... Do the detailing in parallel to researching the material... you will get it done by Xmas then. Otherwise maybe next Easter you will have a GA. Peter

Hi Pete

I am not sure if the general principle to make things stiffer -> make it as big as possible and then make it hollow is always true. At-least this may be the case for small ranges?
I did few simulation runs and results show complete opposite. And this time I did not make that mistake of taking deflection as stiffness. Please see below table where I kept the total mass at around 1315Kg for a particular grout.
And then I reduced the width of the machine and column in steps while increasing the shell thickness so the total weight kept same. The lower the width, the higher the stiffness in all directions.

Total weight	X stiffness	Z stiffness	Y stiffness	Machine width/shellthickness
1315	55.55555556	158.7301587	108.6956522	800/80
1315	69.44444444	181.8181818	142.8571429	600/135
1315	73.52941176	204.0816327	166.6666667	500/160
1323	70.92198582	192.3076923	172.4137931	400/solid

I could not check if this is due to diaphragm effect however.

Thanks
Sus

[suspension]

Sika3350 is expensive stuff.

For parts that don't move, and where weight does not matter that much, you can use lower modulus material.
Your base and column are not space constrained. Just make them fat. Don't bother with hollows.

Use high modulus materials for where space is an issue - e.g. saddles (you don't want a 500mm thick saddle...)

Hi Pippin

You are right. Sika 3350 is expensive to the point where none of the size optimizations are economical. Fortunately I found this one: https://www.chryso.lk/p/8921/chryso-excem-gp-80 which is super cheap compared to Sika 3350 and also allows 50-70% aggregate by weight. (Even without adding aggregates it is cheap). Local company quoted me 16USD per 25 Kg. It has EM47 and 85 compressive strength (very close to Sika 3350). However it only allows 100mm layers without aggregates, need to find out how to handle a fat base and column.

Thanks
Sus

[suspension]

Sorry, I can't open this file, can I convert the format? ?step?xt?igs ?
We look forward to sending you the drawings to my email and I will be happy to help you analyze them.

[email protected]

its a ZIP file, please un-compress it to get the fusion360 file.

[ardenum2]

Hi Pippin

You are right. Sika 3350 is expensive to the point where none of the size optimizations are economical. Fortunately I found this one: https://www.chryso.lk/p/8921/chryso-excem-gp-80 which is super cheap compared to Sika 3350 and also allows 50-70% aggregate by weight. (Even without adding aggregates it is cheap). Local company quoted me 16USD per 25 Kg. It has EM47 and 85 compressive strength (very close to Sika 3350). However it only allows 100mm layers without aggregates, need to find out how to handle a fat base and column.

Thanks
Sus

use cores or cast in pipes, you can run water through them when curing, you'd need to cast in a bunch of thermistors to monitor the temps

[suspension]

use cores or cast in pipes, you can run water through them when curing, you'd need to cast in a bunch of thermistors to monitor the temps

Thanks I will look into that.
Also if I can add aggregates without compromising properties it will give me the added benefit of lesser cost.