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Type: Posts; User: peteeng

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    Re: 14x8x14" Mill Build, Advice Appreciated

    Hi Craig - All of this is covered in the jerk thread I started elsewhere, very big subject. All I can say is that hobby level and lots of commercial level velocity planners are very crude in the...
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    Re: 14x8x14" Mill Build, Advice Appreciated

    Hi Craig - just because we have a trapezoidal velocity plan does not mean it is held to in reality. The path can overshoot, it can undershoot it can do several things depending on the motion planner...
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    Re: 14x8x14" Mill Build, Advice Appreciated

    Hi - There are two main modes of motion in a machine. Feeding and rapids. Rapids require large accelerations for commercial machines to reduce air time. Feeding speeds require constant velocity for...
  4. Thread: Newbie

    by peteeng
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    Re: Newbie

    Hi Stop - Buy a commercial printer that you can afford. They range from cheap to eye watering. Peter
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    Re: Milli a new composite mill kit

    Hi Momentz - Yes I've read you can't use the same rack. With straight rack you can. Thanks I'll send a note to the supplier to see If they have mirrored rack. Thanks for the heads up. The forum comes...
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    Re: Milli a new composite mill kit

    Hi Momentz - I'm currently going with the alignment method vs the spring drive. I think a little patience is worth the result. Good to know it works well once done. The rack is in 1.4m lengths so I...
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    Re: Milli a new composite mill kit

    Hi Momentz - I was going to use 5:1 gearboxes on this one. So that's good - Did you use a spring contact for the pinion or just mechanically aligned? Peter
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    Re: Milli a new composite mill kit

    Hi all you brains out there - I'm designing a 3mx1.5m rack and pinion router with helical rack and pinion drives. Any one done R&P before and have any words of wisdom? I'm nailing down the final...
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    Re: 14x8x14" Mill Build, Advice Appreciated

    Hi Callum - In the rail direction the ballscrew provides the axial rigidity as in the rail direction the bearings are compliant. So take a ballscrew thats D20 and 500mm long. Its stiffness is around...
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    Re: Milli a new composite mill kit

    Hi G - You can also apply 1um deflection to your part and the FE will figure out what the reaction is to achieve that deflection then no brains needed as then you know its N/um immediately... Peter
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    Re: Aluminium printer/milling machine build.

    Hi G - X&Y Ballscrews are sized in a 3 step process. Because they do not lift mass (X&Y) they only need to move the inertia and the friction. Neglecting friction you need to pick a suitable...
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    Re: Aluminium printer/milling machine build.

    Hi G - Here's a link to a BK dimension table. Plus FBT have all the other component dims as well. Peter

    https://www.fbtmotion.com/html/12.html
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    Re: 14x8x14" Mill Build, Advice Appreciated

    Hi Callum - You are travelling down the right path. My suggestion is that you use plate for the whole structure and not use SHS or RHS. This gives you the ability to use the correct thickness as...
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    Re: Milli a new composite mill kit

    Hi G - Convert your results to N/um so we have common units to discuss. What load did you use? I'm sure all commercial FE systems will give the same result if given the same data and geometry. Peter...
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    Re: Lofting the Fuselage

    Hi Well - I suggest you don't do half and mirror it. SW is not sensitive to that sort of issue. If you do half and mirror it you will have to be careful with the curve ends trajectory so ytou don't...
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    Re: Aluminium printer/milling machine build.

    Hi G - I suggest you download one of the main manufactures catalogues and use their numbers. They have detailed dimensional data on their products. Hiwin skf INA etc they all build to international...
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    Re: Aluminium printer/milling machine build.

    Hi G - Thats a local shear transfer tactic. Shear transfer and distribution is something I have had to learn about in this sort of machine design. Machine parts like to be thick. Peter
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    Re: Aluminium printer/milling machine build.

    Hi G - Topological "optimisation" algorithms are generally based on removing low stressed material. This approach often does not develop high stiffness solutions. I can realise all of the weird...
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    Re: Aluminium printer/milling machine build.

    To describe what's happening with Funkier 2 -

    In general the AI has connected all the bearings (with all the other bearings) with ligaments that form triangles.
    1) The saddle area is solid and...
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    Re: Aluminium printer/milling machine build.

    Hi all - The generative design always wants to connect the Z axis to the base... So I tried the automated connection feature. Got this funky shape....Plus others Peter

    edit added funkier 2
    ...
  21. Re: Reducing Diameter of Aluminum Rod for Linear Bearing

    Hi Scott - Buy either round supported rails and suitable cars or square rail and suitable cars. By the time you buy bearings, bits of metal and lots of bolts to make your own linear bearing you will...
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    Re: Lofting the Fuselage

    yes each section needs to be on a separate plane. Peter
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    Re: Aluminium printer/milling machine build.

    Hi - I ran it thru the generative but it attached the Z axis to the bed. I did say make it as stiff as possible and I suppose that's the correct answer. I'll have to add some preventative material...
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    Re: Aluminium printer/milling machine build.

    Hi G - I looked at the model closer and a couple of the cars still had balls. That would be the failure. Anywho I replaced the cars and rails with some dummy geometry and ran the optimiser. The...
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    Re: How to Set Microstepping

    Hello Kolias - The DM556 is a digital motor driver. You set the microsteps and the max current to suit the application. The driver does not do this. What it does do "automatically" is figure out how...
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    Re: Aluminium printer/milling machine build.

    Hi G - I meshed your model. It had a few issues but was good enough to run, then the solver failed so I expect the mesh was poor in some spots. Simplify the cars and I can rerun it. Peter
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    Re: Aluminium printer/milling machine build.

    Hi G - I looked at your model and you will need to simplify the cars. They have tiny screws in them, seals and engraving which the mesher will create lots of elements and connections with. This will...
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    Re: Lofting the Fuselage

    Hi Well - Try a simple loft of one or two sections first. Create planes at the sections you want to loft and draw a circle or a square on each plane. Then use the loft tool to connect them. I'm not...
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    Re: Aluminium printer/milling machine build.

    Hi G - To work through some of your statements:
    1) Producing linear motors is a 20 year project - good luck Hiwin stock them just buy it
    2) I have looked at and built linear bearings and again...
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    Re: Aluminium printer/milling machine build.

    Hi G - Start talking about the static stiffness of the machine. 1000/13= 76N/um which is quite stiff. Even half of that will be fine for machining aluminium... but that's real stiffness not model...
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