[catahoula]

Nice. I use my Creality Ender 5+ 3d printer quite a bit, and have kept that stock workflow: Slice on laptop, SD card in the machine. Might not give the same level of display during option but definitely gets the job done.

[catahoula]

Anyone have thoughts on the relative merits of smaller steppers at 1:1 versus larger steppers at 2:1? Is microstepping enough to account for the loss of apparent resolution?

For example- these Nema 34 4.8Nm motors i'm looking at, which have a relatively flat torque curve at 60V, are down to 2 Nm at 1000 rpm. However, the 9Nm nema 34s are still at 2.5 Nm at 500 rpm. So with a 2:1 belt drive, there is 25% more power available when the ballscrew hits 1000 rpm. And the effect is even more pronounced at lower speeds- 800 rpm with the 4.8 Nm stepper is about 2.2 Nm, while 400 rpm with the 9Nm stepper is producing 3.8 Nm torque. Which might actually be enough to get the machine around 0.1g accelerations.

So I guess microstepping is the big question- does the reduction in torque from microstepping offset the significant increase in torque with a larger, geared up motor?

[peteeng]

Hi Cat - I don't think usteps reduce torque? Where did you get that from? Peter

[catahoula]

Reading more on it now.

https://www.machinedesign.com/archiv...stepping-myths "The real compromise is that as you increase the number of microsteps per full step, the incremental torque per microstep drops off drastically."

Other info suggests that the usable torque isn't reduced because torque per degree of rotation is unchanged.

It sounds like 8-10x microstepping is kind of the real world limitation for microstepping? With 1.8 degree motors and 2:1 drive, full step resolution is 0.05mm or 0.0019", not great, but divided by 8 is small enough.

[catahoula]

I guess I'm a visual person. Plotted a comparison and it helped settle the decision making- 34E1K-45 is the clear winner for useable torque, enough to drive the ballscrews at 1:1. And per Pete's calc, it could possibly handle 0.1g accelerations on my machine up to about 600 rpm motor speed or 3000 mm/min feedrate. (these specs are i think all with the CL86T driver @ 60 volts). I think I'll use a braked motor on the z-axis for good measure. The 2:1 concept with a larger motor probably has potential but I don't want to risk loss of resolution, plus the larger 9 Nm motors would be getting pretty heavy.

[peteeng]

Hi Cat - You found the spreadsheet straightforward to use? Your the first person to say you have used it... Peter

[catahoula]

Well, I like numbers but I hate real math. So it's perfect

[Mr-MaW]

Hi Cat - What are the restraints in the model? If you are restraining the base feet the model will be much stiffer then in practice. Restrain the table or better still say a block "vice" on the table so the load loop goes from the tool to the vice which is then correct. CSA or UHPC start at 26GPa and through to 80GPa. Epoxy granite starts at 20 and can get to 40 as epoxy has poor stiffness. cheers Peter

Yep, it's not clear in that photo but the restraint is a 200x200x12 square plate in the middle of the moving table- that way the table and frame are free to flex. The typical use for this machine is milling aluminum molds about 300 x 180 x 75mm, so I think it's a reasonably accurate setup.

Well, I like numbers but I hate real math. So it's perfect

SO,I like
Nice to meet everyone.
If you need mineral castings.You can contact me, my email:[email protected]
I'm from China,My company has produced a lot of products, small can reach 100KG, large can do 46 tons.
My English is very average and I don't know how to upload photos. Very reason to share my product with you.
https://grabcad.com/library/cnc-lath...ral-castings-1

[catahoula]

Taking advantage of the Thanksgiving holiday to get a bit of work on the CNC in. Welded the stand for the machine, which I hadn't gotten around to yet. Did a couple hours of drilling and tapping today. The machinist didn't want to drill the M5 holes because his spindle rpm was too low and thought he'd just break bits, but he did center drill the locations, so I picked up one of these portable drill presses and mounted it to a board that I knelt on. Worked quite well. The gantry holes are M6 so those were drilled but a lot of hand tapping nonetheless!

Next step is doing a temp assembly on the machine base to get the base and pillars and gantry aligned. Mark hole locations and drill. Then disassemble, flip the base over and pour the epoxy-sand mixture in the hollows. Flip back over and do the final assembly. The gantry will be bolted and epoxy bonded to the pillars; the pillars will be bolted to the base (with epoxy bedding after final alignment).

Then it's on to assembling the edingCNC controller and motors that I ordered in the spring.

Machine stand is upside down in the photo. Made of 3x3" square tube 3/16" wall with the main tubes filled with sand

[peteeng]

well done, hope your knees survived. I see you used knee pads.... - Peter

[guochao]

Fastener manufacturer
As an outstanding fastener manufacturer and supplier, Panda Fastner has more than 20 years of production experience and international trade experience, providing customers with relatively professional and complete fastener solutions. You can consult them specifically if necessary.https://www.pandafastener.com/

[catahoula]

well done, hope your knees survived. I see you used knee pads.... - Peter

Knee pads are my personal winter 23-24 revelation Almost any kind of house work is so much better with em

Finally got big long 300mm reach magnetic base indicator holder, farted around in the garage this eve for a bit and got the y rails within +/- .005 mm straightness and parallel from my reference straight edge. I was so pointlessly worried about that process when I was designing it. Although I'm also scheming on a technique to use epoxy to create some permanent shoulders for the master rail once it's final assembled and indicated but leave the rail removable.

Couldn't find a darker teal in hardware store enamel spray paint but this turquoise is nice enough

[peteeng]

Hi Cat - Teal hammertone! yeh baby! Peter

[routalot]

Knee pads save a lot of discomfort but my experience of using them all day,every day for a few weeks is that they encourage sweating in the area they cover and wet skin softens after a comparatively short while.It also feels the cold very rapidly if you are walking across the car park when its a few degrees below freezing.Other than that,they do save pain.
Nice choice of colour and you are about to find out how time consuming a good paint job is.It does make the machine look a lot more professional when done well.

[catahoula]

Painting is definitely a pain and I'm not particularly looking forward to it, but that said, the frame has quite a bit of stitch welding, so even a careful job isn't going to look amazing, and I'm not planning on doing anything like using bondo of over all the rough areas to smooth it out. So going for functional quality and good adhesion- a little extra grinding to clean up the surfaces, driveway sandblast, lots of solvents, self etching primer, 2 coats of color and a coat or two of gloss over the top. However that looks I'll be ok with.

[catahoula]

Did some manual milling on the spindle plate at a friend's garage last night and this afternoon. With the temps dropping to -30 C we were willing to blast the tank top propane heater and keep the doors closed up

I did manage to lose track of which side has the pocket and which has the countersink, so had to drill a new set of holes for the ballscrew mount, but no big deal. This is the first assembled ballscrews so very fun to see it go together.