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Type: Posts; User: jackjr-123

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  1. Replies
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    Re: Benchtop mill-drill

    Hi Peter, that makes sense, thanks for explaining.

    Today I tried making a small batch (2kg) of UHPC with the standard E45 recipe. It was a complete failure.
    I mixed by hand and with the help of a...
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    Re: BST automation vs dy-global eBay

    I might be a bit late, but avoid if you can. Those IKO LM guides are old designs with 2 rows bearings. State of the art bearings are 4 rows in O arrangement for much better stiffness.
    Even Hiwin HGR...
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    Re: BST automation vs dy-global eBay

    Seems like you know better than TBI themselves, so no point in arguing anymore.

    I meant absolute pitch, I edited my previous message. The pitch consistency is what you get with ground screws, and...
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    Re: BST automation vs dy-global eBay

    Sorry but you have no idea what you are talking about.
    I still can tell what is ground and what is not.


    Also absolute pitch accuracy is not a big deal. The ballscrew can be mapped. The main...
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    Re: BST automation vs dy-global eBay

    I cannot disagree more. I've ordered a bunch of ballscrews over the years. All C5 or C3 ground. The last one I bought a couple of weeks ago was a TBI 1000mm 2005 C5 ground with custom end machining...
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    Re: BST automation vs dy-global eBay

    I think you should finalize your design before buying more random parts and trying to make them fit :)

    But yes you can buy bars of Blanchard-ground steel and bolt them. This is my go-to supplier:...
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    Re: Milli a new composite mill kit

    This is exactly why you should NOT buy the cheapest Chinese servos, they are an exercise in frustration. The Delta ones have decent software and documentation.
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    Re: Milli a new composite mill kit

    Well there is simply no speed regulation. The actual spindle speed will vary with the load. And also the low torque below rated speed.

    Peter,
    I recommend avoiding these Chinese servos. For little...
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    Re: Milli a new composite mill kit

    I just didn't remember very well... My motor is rated at 3.2 Nm not 3.4 Nm, hence more confusion :)
    I'll double-check next time.

    I'm curious though what kind of VFD you'll be using. From my...
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    Re: Milli a new composite mill kit

    That sounds right. I missed the part where you said it's a 3.5kW motor. Mine is 5.5kW, hence the confusion.

    Even if the torque is enough for some steel milling, you also have to keep in mind that...
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    Re: Milli a new composite mill kit

    I have one of these spindles. With the Chinese it's hard to get correct information. While asking for the torque/frequency curve of the motor I got 3 different replies, and their VFD settings were...
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    Re: BST automation vs dy-global eBay

    These are support units from SYK (Taiwan) and they are top notch. Exact same performance as THK/NSK ones for a fraction of the price.


    Craig,
    Again, there is nothing special about matched...
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    Re: BST automation vs dy-global eBay

    There is really nothing special about those bearings, they are just standard 7xxx bearings in P5 or P4 quality. The ridiculous price tag from THK/NSK doesn't mean anything.

    Also these support...
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    Re: Aluminium printer/milling machine build.

    Longer carriage: more balls, more load capacity, higher stiffness.
    Flanged carriage: less tall, higher lateral stiffness.

    So for machine tools you usually want to go with the longest flanged...
  15. Re: Advice needed for parts selection for new DIY CNC Mill

    According to my sims a steel column will be about 50% stiffer than a UHPC (E45) column of the same volume and mass. But you're right that the steel one will be more expensive and requires more work.
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    Re: Benchtop mill-drill

    Peter, thanks for all your advices.
    Not sure what you mean by "restrain the cars at the arm" ?

    I worked on sims all day long and overall stiffness seems to be "death by thousand cuts".
    One...
  17. Re: Advice needed for parts selection for new DIY CNC Mill

    No I'm in Europe. I can't find any settings to change my location...
    If you want some Durigid I could send you some.
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    Re: Benchtop mill-drill

    Yes the saddle needs work. However as is there is no issue with the carriage mounting bolts. First the saddle plate alone is bolted to the Y axis carriages, then the whole assembled table is laid on...
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    Re: Benchtop mill-drill

    The above sims are obviously not a pure bending load since the base is fixed on 3 points with 2 of them directly below the column bearing surfaces. With a pure bending load the steel base is indeed...
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    Re: Benchtop mill-drill

    Weird the pictures show up fine here. Let me try again.
    502114 502116


    I don't mind aluminium, but bolted designs are already a lot of work. If you need to add ribs everywhere it becomes...
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    Re: Benchtop mill-drill

    This is the steel base (15mm plates, hollow) vs the UHPC one. Quick sim with 3000N on the column bearing surfaces.
    Steel base is 132kg vs 120kg UHPC.
    502110502112
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    Re: Benchtop mill-drill

    About machining: the only machining allowed is the one I can do myself. I can use my previously built CNC with 640x500x250mm travels (a fixed gantry design, mainly designed for aluminium milling). It...
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    Re: Benchtop mill-drill

    I also thought that steel had the best stiffness/weight performance for the base, and I tried making a steel base (simple box shape). I ended up with a heavier and less rigid result according to the...
  24. Re: Advice needed for parts selection for new DIY CNC Mill

    Good question :)
    I didn't think much about it, but I was thinking a beam supported on both ends, the load in the middle and a DTI measuring the deflection.
    How would you do it?
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    Benchtop mill-drill

    Hi all,

    I've been planning on building a small benchtop mill-drill, about the same size of a RF45.
    Yes I know I could spend only $3000 and get a chinese RF45 clone, but I prefer starting from...
  26. Re: Advice needed for parts selection for new DIY CNC Mill

    I've ordered some Durigid stones to try making this elusive E80 concrete. I'll make a few samples with the exact Nanodur recipe and test the stiffness.
  27. Re: Advice needed for parts selection for new DIY CNC Mill

    Epoxy shouldn't be dismissed because of it's relatively low stiffness. Turcite's Young modulus is 0.7 GPa yet is widely used on box way machines. Surface and contact area make all the difference.
    ...
  28. Re: Advice needed for parts selection for new DIY CNC Mill

    Thanks for your replies.

    I was thinking that using a thin layer of epoxy would improve the stiffness and lessen the number of bolts needed. And when I mean thin I mean gap-filling in the 0-0.1mm...
  29. Re: Advice needed for parts selection for new DIY CNC Mill

    Peter,

    Let's say you want to build a box section with 15mm steel plate and M6 bolts.
    How would you choose the bolt spacing for optimum stiffness? Is there some rule of thumb?

    What if the...
  30. Re: UHPC+steel fixed gantry router/alu mill machine build

    Thanks. I've seen Durcrete documents, but their recipes are confusing. Sometimes there are fibers and shrinkage reducer, sometimes there are none of them...
    I think I remember reading that the...
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