Problem: Losing Steps?

[dazp1976]

Fasttobuy also on ebay.

https://www.ebay.co.uk/itm/124976751...YAAOSwighZlpWS

[Chattygt]

Hi,
if you are interested in servos look into Delta (Taiwanese made in China) and DMM (Canadian made in China). They are both good quality
with high resolution encoders, good backup, good documentation and most importantly free set-up and tuning software at very fair prices.

There are many hundreds of parameters that need to be programmed into a modern servo drive. If you try to program them by pushing buttons like a
microwave, you'll be there forever and STILL make a mistake.

https://www.fasttobuy.com/Supply-asdab2-series_c498

There are even cheaper Chinese made brands, Liuchan and ToAuto, come to mind. they are very well priced and attractive as a result, but the documentation is poor
and no set-up and tuning software. I have no reason to doubt their quality or performance, its just hard to set them up, especially if this is your first foray into servos.

Modern AC servos from all manufacturers tend to be very similar in terms of features and programming. If you've done one you've done them all. Delta and DMM
are typically 25% more than Liuchan and ToAuto and well worth the extra.

Many servo-newcomers favor Clearpath servos, and they are very good quality and industry leading after sales support but they are expensive for what you get.
Firstly Clearpaths have as standard a paltry 800 count/rev encoder, one, only one, digital output, no auxiliary outputs and no analog inputs.
A 400 W (actually 397W) Clearpath servo is $517USD while I paid $435 for a Delta B2 servo (160,000 count/rev)...that's twice the power for less.

Craig

Thanks for the info Craig. I've actually been looking at the dmm servos as I live in Canada. Trying ti decide between their dyn2 or dyn4 units. Then I can decide just how big I need. My current motors are nema 24 with 1/4" shaft, 38.1mm diameter mounting. If I can find one to bolt in, would be ideal but if not, not the end of the world.

[joeavaerage]

Hi,
I'd go for the Dyn4 types, they are such a small extra outlay and it means you don't have to get an external power supply.
My Deltas are all 230VAC input, ie no external supply required, dream to use.

Delta 750W B2 series are sort of the 'entry level' and are very well priced. I took delivery of a 750W B2 and a 400W B2 just before Christmas
and paid $435 for the 750W and $390 for the 400W. I suspect you'll find the same with DMM, the higher power is only marginally more,
and so the more powerful makes sense.

The 400W Delta is 60mm or 24 size and so would be a bolt in replacement, although you'd have to bore the pulley out a bit.

What is really impressive about servos is their overload capability. When the load comes on they just 'dig in' and do the job, whereas a stepper just stalls,
no ifs or buts, it just stalls. Consequently a servo seems to outperform relative to its spec, but given the cost difference why not have more power?
I would say 400W servos would make your machine fly.

Craig

[Chattygt]

Hi,
I'd go for the Dyn4 types, they are such a small extra outlay and it means you don't have to get an external power supply.
My Deltas are all 230VAC input, ie no external supply required, dream to use.

Delta 750W B2 series are sort of the 'entry level' and are very well priced. I took delivery of a 750W B2 and a 400W B2 just before Christmas
and paid $435 for the 750W and $390 for the 400W. I suspect you'll find the same with DMM, the higher power is only marginally more,
and so the more powerful makes sense.

The 400W Delta is 60mm or 24 size and so would be a bolt in replacement, although you'd have to bore the pulley out a bit.

What is really impressive about servos is their overload capability. When the load comes on they just 'dig in' and do the job, whereas a stepper just stalls,
no ifs or buts, it just stalls. Consequently a servo seems to outperform relative to its spec, but given the cost difference why not have more power?
I would say 400W servos would make your machine fly.

Craig

Fantastic. I'll work towards pricing out that route. I believe it would make the machine more suitable long term as well. I own a small custom machining shop, would be nice to have a dependable machine.

[dazp1976]

Fantastic. I'll work towards pricing out that route. I believe it would make the machine more suitable long term as well. I own a small custom machining shop, would be nice to have a dependable machine.

Decent deal B2:
https://www.aliexpress.com/item/32918315088.html?spm=a2g0o.productlist.0.0.ee1c2a6 1L5aUz2&algo_pvid=223ec399-b5a5-4531-adb2-acc7b35be353&algo_exp_id=223ec399-b5a5-4531-adb2-acc7b35be353-8&pdp_ext_f=%7B%22sku_id%22%3A%2265969890451%22%7D &pdp_pi=-1%3B237.81%3B-1%3B-1%40salePrice%3BGBP%3Bsearch-mainSearch

https://www.aliexpress.com/item/3296...rch-mainSearch

B3. (higher res?):
https://www.aliexpress.com/item/1005...rch-mainSearch

[joeavaerage]

Hi,
both of those prices are very sharp indeed.

To be honest I've always been a bit nervous about splashing my credit card around to a company I don't know. On the basis of favorable feedback from
other buyers I settled on Fast-to-Buy which has an Ebay presence and a straight out on-line web presence. Over a couple of years and four transactions I'm now very
confident in the supplier. You have found an even cheaper source for a 400W B2, $54 cheaper than I paid just before Christmas, but I'm happy with my supplier.
$54 does not even come close to the shipping cost to New Zealand....so I'm not going to get too worked up about it.

You are correct there are a number of different models.

The current entry level model is the B2 series, which has a 160,000 count/rev encoder. This is the cheapest model and what I'm familiar with and I am extremely
impressed with it performance and flexibility. The previous A, B and AB models are discontinued, so don't be caught buying new old stock.

The next step up is the A2 series. It has a 1,280,000 count/rev encoder but even more importantly it has a secondary encoder input channel to close the position loop.
This feature means the torque and speed loops are closed at the drive with the built-in rotary encoder per normal (B2 style) but can have, say, a linear encoder attached to the
axis to close the position loop. This is the last word in position control. At the time I did not know about this extra feature of the A2 series otherwise I might have sprung the extra
$50 or so to get them, not that I have linear scales.

The question you need to ask is 'does my project require load sensing position feedback?'. With my new mill I've used 32mm 5mm pitch ground C5 THK BNFN double nut ballscrews.
To achieve my desired level of accuracy, 0.01mm, I do not need load sensing and therefore the cheaper B2 series are more than adequate. If you have lesser ballscrews, or backlash,
or alternately desire 1um type accuracy, either now or in the future then the A2 series is the way to go.

There are two even more recent models.

The A3 series has a 24bit absolute encoder, something like 16,000,000 count/rev, and I presume load sensing capability as well.

The latest model is the B3, with the same absolute 24 bit encoder but multi-turn, and battery backup. This would mean you can come along and turn on your
machine and it will know where it is, not only within one rotation of the servo, but multiple turns from its nominal home position, WITHOUT having to be Homed!
All-in-all a very sophisticated product.

Note that Delta are far from the only servo manufacturer that have such advanced features. I'm less familiar with DMM but other forum users have posted that DMM
has a very similar suite of features as do all the US, Japanese and European manufacturers.

One of the attractions, at least for me, about Delta, was affordable quality and performance. Sure I can get even greater performance from the latest models but rather lose
out of the 'affordability' aspect. As it turns out I hardly ever come close to taxing my humble B2's to 10%, they have more resolution, power and speed than I can handle.

Craig

[dazp1976]

I'm not in the market yet for servos but have had no problems from Aliexpress sellers.
I'll be upgrading screws first to maybe the TBI C5 double nuts.
I've been sold on the delta by Craig. One good thing going for them as well is the availability of the cables.

I do like the Lichuan A4 set I already have for a spindle drive upgrade and it bench tested well in all areas of usage.
However the encoder count is average and you'd prob class it as slightly basic but is very easy to use. (once you get your head round it).

The other downside is documentation is OK but not comprehensive. I used manuals from other drives to get my head round some areas as most drives have similarities in wiring schematics. Had a good bit of help on here too.
Lichuan do have a 'debugging' software available but I have not had it set up.

[dazp1976]

Hi,
I'd go for the Dyn4 types, they are such a small extra outlay and it means you don't have to get an external power supply.
My Deltas are all 230VAC input, ie no external supply required, dream to use.
Delta 750W B2 series are sort of the 'entry level' and are very well priced. I took delivery of a 750W B2 and a 400W B2 just before Christmas
and paid $435 for the 750W and $390 for the 400W. I suspect you'll find the same with DMM, the higher power is only marginally more,
and so the more powerful makes sense.
The 400W Delta is 60mm or 24 size and so would be a bolt in replacement, although you'd have to bore the pulley out a bit.
What is really impressive about servos is their overload capability. When the load comes on they just 'dig in' and do the job, whereas a stepper just stalls,
no ifs or buts, it just stalls. Consequently a servo seems to outperform relative to its spec, but given the cost difference why not have more power?
I would say 400W servos would make your machine fly.
Craig

Deleted.
Due to human error

[Chattygt]

Just an update, spoke to DMM via email, they recommended their 400w motors and dyn2 drivers.

Recieved all the pieces and cables, bench tested and installed. Just got it wrapped up last night. Got the servo drives tuned and controller steps dialed in.

Going to be fine tuning the acceleration and deceleration.

All is good so far, I can't believe how quiet the machine is now.

[joeavaerage]

Hi,
yes, servos are a world apart from steppers, you pay a premium for sure, but you so get what you paid for.

Craig

[dazp1976]

Hi,
yes, servos are a world apart from steppers, you pay a premium for sure, but you so get what you paid for.
Craig

Hmm.
Just came across some ok looking 400w Mitsubishi servo sets. Put in a 'cheeky' offer, doubtful but you never know.
MR-J3-40A driver MR-JE-40A driver with HF-KP43 motors


They'd only end up in storage as well though I bet

[dazp1976]

Just an update, spoke to DMM via email, they recommended their 400w motors and dyn2 drivers.
Recieved all the pieces and cables, bench tested and installed. Just got it wrapped up last night. Got the servo drives tuned and controller steps dialed in.
Going to be fine tuning the acceleration and deceleration.
All is good so far, I can't believe how quiet the machine is now.

Sounds good
Hope you have many hours of chipping.

I was too torn over the used ones I was looking at. Decided to buy myself a 50L air compressor instead
I'll be looking to the Delta's when the time comes.
Importing items like the DYN4 sets from US. to UK. is stupid money.

[joeavaerage]

Hi,
what gives with the UK and imports? I thought the whole idea of Brexit was to make the place more competitive?

The vast majority of parts and materials imported into New Zealand attract NO import tax whatever......correction, they get G(oods) and S(ervices) T(ax) of 15%, but that applies
to everything. I understand you have to pay 5% sales tax on clothes and 10% on shoes...God only knows why, and who knows how much for booze or tobacco....but thats it.

Craig

[dazp1976]

Hi,
what gives with the UK and imports? I thought the whole idea of Brexit was to make the place more competitive?

The vast majority of parts and materials imported into New Zealand attract NO import tax whatever......correction, they get G(oods) and S(ervices) T(ax) of 15%, but that applies
to everything. I understand you have to pay 5% sales tax on clothes and 10% on shoes...God only knows why, and who knows how much for booze or tobacco....but thats it.

Craig

Dragging thier heels on it all.
It's called 'rip off Britain' for a reason.
The 'admin fees' alone that the postal services charge are as bad as the tax.
There's a s**t ton of 'domestic dwellers' that have cottoned on to ordering stuff direct from China.
Even if we get hammered at the border on some stuff, our own stores still cannot match cost on most of it. (that's even if it's avail here).
I gave up on u.k. because of the severe lack of availability and now most of my garage is Aliexpress!!!!!!!!.

And they wonder why businesses are going under!!.

Even down to my daughters led light strips for the bedroom. Paid under £10 from Ali-ex all in. Same kit here £20+.
And if any item is over 25mm thick you're looking at extra £3+ for domestic shipping.
How do Ali-ex ship it here free???.

[joeavaerage]

Hi,
so how about putting some number on it. I you import a gadget worth $100GBP how much tax do you pay?
Does it vary depending on the country of origin? Lets exclude booze and tobacco...we all know they get taxed to hell.
Does the tax vary according to the type of product?

Craig