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Hi Pio:
1) thermal issues for a machine in a flat is unlikely to be a problem when aiming at a Hobby level machine. The principles of thermal symmetry if they can be applied is worthwhile especially...

Hi Craig - Garden fountains are a useful distraction. Peter

Ok - sounds like a good plan. Peter

So Vily - Do you intend stress relieving the weldments? This is best practice (and least risk for being able to machine the lands flat) and how are you going to machine the lands for the rails? The...

Hi Vily - I find using std SHS and RHS to be a limiting approach. But if your going to use it, select the biggest heaviest sections possible or combinations to create the biggest geometry possible....

Hi Vily - If any tool is not trammed then one side is higher than the other and will cut a scallop into the surface. The bigger the tool the bigger the error vs the same off axis amount. All tools...

Hi Vily - By tramped I think you mean Trammed? If it is not trammed correctly the bigger the tool the bigger the error. Also the commercial machine builders that fabricate machines do not fill their...

Hi Vily - very good. Why using a fly cutter? They are used to reduce the load on the machine and do not have a very big material removal rate. Speak to your tooling supplier about tools suitable for...

Hi Vily - If you intend doing a lot of face work on plate then consider using a bolster or a sub table on the machine. This will minimise the Z height. If you design a machine with a "big" Z then you...

Hi Vily - thicker steel is better than adding concrete. Keep making things as big and thick as possible. The z axis is what will let you down so make it very stiff. So on that point here's my...

Hi Pio - A couple of things. What sort of machine are you aiming at? Maker/Hobby level? Commercial? Toolmaker grade? and what do you want to do with it? Your design is clearly above say a Taig but...

Hi Andrew - I don't think so but best to send Tom the question. I have not used the product yet, will use it on the next two machines in build. I have been reading the manuals and threads plus Tom...

Hi Pio - What modulus are you using for the concrete? If your model is correct (so check all the connections and geometry) then the spindle nose static stiffness is 300N/37um ie 8N/um. This is not...

Hi Andrew - Look at dynomotion will do as you need, has excellent motion control and Tom provides excellent support. https://dynomotion.com/index.htm Kflop is 8 axes out of the box and...

Hi Vili - I've recently been thru the Z axis using generative, shape optimisation and form finding in Fusion,. The tube idea was the winner. I expect it to be a bigger stiffness gain then 33 to 26 so...

Hi Vily - So 1000N/33um is 30N/um. So if your model is correct look at what bits are deflecting the most. Then address those. Try to bump up the static stiffness. Seems your z axis is the softest...

Hi Vily - Unfortunately, with steel things get heavy. So you are either limited to weight that you can handle or you need to achieve a certain stiffness. See how you go with the FE and stiffness....

Hi Vily - That small free corner will vibrate so cap it. OK FE is a big subject. I apply 1000N at the spindle nose. Use bonded connections everywhere to begin with. Place the gantry at max depth...

Hi Vily - So its 300 high and 200wide? Internal bracing not needed. External bracing has to be on edges not in the middle of a face. It can deflect / vibrate if loaded in the middle of a face. The...

Hi Vily - The HAAS GR-712 gantry machine with X=2.1m and Y=3.6m (similiar to yours) weighs 10 tonne for a reason.

GR-712 | 40-Taper Mill | Large-Platform CNC Routers |Vertical Mills – Haas CNC...

Hi Vily - so on the point of rigidity add an extra section to the back of the gantry. Most of your loads will be in the XY plane so this needs to be stiff. It takes up no extra space in the envelope...

Hi Vily - up to you. Since its a paper exercise at the moment develop both ideas until you are clear for the direction. Mixing servos and steppers is OK. A 5mm pitch screw only needs...

I would say 750W is overkill with the big gearbox on it for Y's Yes you can attach the servo direct to the X ballscrew same as the stepper Oh use a coupling :) Once you figure your needed feeds and...

Hi Vily - The gantry+Z axis is on rails so your only moving the inertia and the friction. Since the friction coeff of the rails is very low say 0.004 you only need 0.004x400=1.6kgf to move it slowly....

Hi Vily - No the holding torque for the motor stays the same so at zero speed you have the full 12Nm. So double the forces just calculated. So at 12Nm (stall or very slow) and 10mm pitch you have...

Hi Viny - What is the weight of your gantry? I see 400kg The Co for a 35mm car is around 70kN ie 7000kg so 3 cars can support 21 tonne? They must use 4 for some other reason... They may use 4 for...

Hi Vily - No need to fill with sand. Ballscrew for X at 5mm pitch is too small. Using stepper say 800rpm max gives you 4m/min rapid. Not fast enough, use 10mm or more. 3 cars on column not needed....

Hi all - Looking at my rotary say D400mm then the planetary at 15arcmin (0.25deg) gives 0.87mm backlash and the harmonic at 30arcsec (0.0083deg) gives 0.028mm backlash so sorting the harmonic for...

Hi all - I have been looking at these harmonics. But I'm unsure which is the output holes or surfaces. I have sent a note to the supplier to explain. Currently my guess is that the D14 is the input...

Hi Craig your machine is a mill and requires higher tolerances then this machine. Mine is a Maker level router for wood and plastics, and being #1 its at preproduction level. I'm sure the tolerance...