NordicCNC's build log

[NordicCnc]

Okay I now have a dilemma.

The price difference between 400W and 750W Delta servo motors are only about 100€ each, so total of 400€ price difference. This means that I would get 2 times the torque if deciding to go for 750W servos. Anyway are there any possible drawbacks with these huge servos other than more space requirement and somewhat more expensive? Larger pulley diameters would be needed due to 19mm shafts instead of 14mm shafts.

Also would 400W servos have enough torque to spin 2020 ballscrew with a 2:1 ratio? That would give me a speed of 30m/min. Same case with 750W servos, but those would for sure have enough if not too much available torque.

Also do I need that kind of speed for anything? Machine working area is approx 1200x1000mm anyway. Perhaps 15m/min (achieved with 2010 ballscrews) would be more than enough.

I need help. Please advise!

Some info that might be useful:

• Z-axis weight: 27kg (1605 ballscrew, 2:1 ratio)
• X-axis weight: 60kg (2020 or 2010 ballscrew, 2:1 ratio)
• Y-axis weight (gantry): 120kg (dual motor drive, 2020 or 2010 ballscrew, 2:1 ratio)

[JAZZCNC]

400W with a 2:1 on 10mm pitch will be fine. The ratio will double the torque and Like you say you won't need more than 15mtr/min, in fact, you could go 3:1 or 2.5:1 and still have plenty of speed.

Save the money and put the 400 into better ball screws.!

[NordicCnc]

400W with a 2:1 on 10mm pitch will be fine. The ratio will double the torque and Like you say you won't need more than 15mtr/min, in fact, you could go 3:1 or 2.5:1 and still have plenty of speed.

Save the money and put the 400 into better ball screws.!

Thanks JAZZ. I am now waiting for a quote from DMM Technology for 400W servo motors. Their servo motors looks really good and the manual/software as well!

The ballscrews that I was planning to get arw C7 rolled ballscrews from BSTmotion. I guess the next step would be either:
1. C7 rolled, with double ballnut
2. C5 ground, with single ballnut
3. C5 ground, with double ballnut

I think that Fred doesn't offer C5 ballscrews so I am mot sure where to buy those from!

Edit: I looked into it and I will probable have a go at double ballnuts. I may need to increase the ballscrew lengths to maintain the same working area, but it will be well worth!

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[JAZZCNC]

Thanks JAZZ. I am now waiting for a quote from DMM Technology for 400W servo motors. Their servo motors looks really good and the manual/software as well!

The ballscrews that I was planning to get arw C7 rolled ballscrews from BSTmotion. I guess the next step would be either:
1. C7 rolled, with double ballnut
2. C5 ground, with single ballnut
3. C5 ground, with double ballnut

I think that Fred doesn't offer C5 ballscrews so I am mot sure where to buy those from!

Edit: I looked into it and I will probable have a go at double ballnuts. I may need to increase the ballscrew lengths to maintain the same working area, but it will be well worth!

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Never used DMM but I've heard good and bad things so who knows, you just have to try then make up your own mind.!

Ask fred about C5 because I've had C5 from him before and I think he even has or can get Ground screws in shorter lengths. Unless they have stopped supplying them.?

You have to stop at some point because you can go on for ever choosing better quality or performance parts, each upgrade usually affects some other area which then needs upgrading to match else it's pointless. The better machine isn't the one with a few high spec parts, the one that uses lower spec parts that are evenly matched will be the more balanced machine and overall usually work best. . . . Remember machine is only as good as it's weakest link, upgrade one area the rest becomes weak.!!

[NordicCnc]

Never used DMM but I've heard good and bad things so who knows, you just have to try then make up your own mind.!

Ask fred about C5 because I've had C5 from him before and I think he even has or can get Ground screws in shorter lengths. Unless they have stopped supplying them.?

You have to stop at some point because you can go on for ever choosing better quality or performance parts, each upgrade usually affects some other area which then needs upgrading to match else it's pointless. The better machine isn't the one with a few high spec parts, the one that uses lower spec parts that are evenly matched will be the more balanced machine and overall usually work best. . . . Remember machine is only as good as it's weakest link, upgrade one area the rest becomes weak.!!

Can you specify some of the bad things? But, yes I will most lilely go for these anyway. Many have used them with great success. The manual and software is really good (not chinglish!) There must be bad things about the Delta servos also.

Fred can supply C5 ballscrews but it will be TBI brand and expensive (about 2.5x more expensive)!

This I have noticed, haha. I have saved every iteration of the machine design. I am up to v11 now..



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[JAZZCNC]

Can you specify some of the bad things? But, yes I will most lilely go for these anyway. Many have used them with great success. The manual and software is really good (not chinglish!) There must be bad things about the Delta servos also.

It's been a while but it mostly related to the encoder's output from the drives when using with a controller that can fully close the loop. There were some timing issues that caused problems between controller and drive. But that was some time ago so they will have probably resolved that issue by now but I've seen all kinds of little things and conflicts on various forums etc.
But like you say Delta and other manufacturers do have there own issues as well and it's how they are resolved that matters most, DMM are very good in this respect I believe,

[NordicCnc]

Does anyone know what size cable drag chain is preferred? I am thinking about 25x77mm: https://www.aliexpress.com/item/5300...264066ec24hVi7

[AndyUK]

Does anyone know what size cable drag chain is preferred? I am thinking about 25x77mm: https://www.aliexpress.com/item/5300...264066ec24hVi7

Depends on the amount and size of your cables! I measured the diameter of each, approximated them as square boxes, and then calculated the internal area needed. Then you want to fill to about 60%.

[NordicCnc]

Short update to show the final design. NO MORE CHANGES! Started ordering parts today, I am excited.



Not sure if the frame and/or table needs more bracing. Please give me some advice!

[NordicCnc]

I know I said no more changes but I was wrong. I modified the frame and bed quite a bit. All parts are now ordered and the first parts will be arriving in the beginning of next week. The bed will be adjustable in height to allow for higher work parts if ever needed. This is a safety measure so that I don't regret the design. Table will be adjusted with scissor lifts and should be quite easy to realign. I will also add some triangle bracing to the frame, which are not shown in the pictures. These will be made of steel.

Oh and by the way, budget of 8000€ was not enough, which I expected anyway. It will be closer to 10000€. I am still happy!

Also JAZZ was right in the beginning of the build log about the total weight. It will be over 400kg once everything is assembled.



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