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High loadable turntable

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Re: High loadable turntable

Postby milz » Tue Mar 10, 2015 9:18 am

heho
I have build two big turtables and plan to build a small one next
in my experience is better to use beltdrive and microstepping.
or you need a code a PID function for smooth start and stop.

mfg milz
Xeon x5650@4ghz
Cam : USB2 CCD 1024x768 / USB3 1280x900
Laser : LC532-5-3-F(16x65) Focusable Green
Projector Acer X110P / Acer K132
dControl one David control box + Turntable + automatic texture lights
mooooom bathroom!!!!!!
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Re: High loadable turntable

Postby WalterMo » Tue Mar 10, 2015 9:58 am

milz wrote:heho
I have build two big turtables and plan to build a small one next
in my experience is better to use beltdrive and microstepping.
or you need a code a PID function for smooth start and stop.

mfg milz


Have you recreated this turntable with the gear ring?
Have you seen how smooth it starts and stops?

A PID (proportional, integral, differential) control system is very complex and elaborate. It's not comparable to the simple design with the stepping gear motor. And ¼ step is already micro stepping.

Walter
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Re: High loadable turntable

Postby milz » Tue Mar 10, 2015 10:34 am

Hi
nice project at all -)
Is there a video from the running turntable ?
I know the gearbox you use. got the same here for tests.
I use http://shop.drehteller.com/Drehkraenze/ ... ::102.html .
not sure how fast your turntable turns -) i had problems with speed. if it run to fast i had to fix/glue the object to the turntable
doublesided gluetape...
otherwise is runs to slow the scan is faster then the turning -)
specally if you have expensive or breakable stuff for scanning a extrem smooth turntable is usefull.
i had objects where i stand beside the turntable with my hand near the objects to prevent damage ...
so i tryed to add a ramp with the I part of the PID.
PID is a bitch .... i ask an pysican and a engeneer both said the didnt understand PID 100%.
my last 2ß-30 scan i did without a turntable. turn it by hand cause david is so fast turn wait 2 sek. turn wait 2 sek.
has the advantage of human eye control for the scan corner / undercuts ...

mfg milz
Xeon x5650@4ghz
Cam : USB2 CCD 1024x768 / USB3 1280x900
Laser : LC532-5-3-F(16x65) Focusable Green
Projector Acer X110P / Acer K132
dControl one David control box + Turntable + automatic texture lights
mooooom bathroom!!!!!!
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Re: High loadable turntable

Postby WalterMo » Tue Mar 10, 2015 12:06 pm

milz wrote:otherwise is runs to slow the scan is faster then the turning -)

Don't set a hook at 'Auto Add to List' or 'Align to Previous Scan'. So a synchronisation between scanning and turntable rotation is fine. (If you program the table like me).

milz wrote:PID is a bitch .... i ask an pysican and a engeneer both said the didnt understand PID 100%.

Years ago I had tried to build a PID controller for a DC gear motor with some operational amplifiers. At that time my first grey hairs appeared. :(

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Re: High loadable turntable

Postby milz » Tue Mar 10, 2015 12:15 pm

WalterMo wrote:Don't set a hook at 'Auto Add to List' or 'Align to Previous Scan'. So a synchronisation between scanning and turntable rotation is fine. (If you program the table like me)
Walter


hehe nono i mean not the sync thats no problem. but if the turntable runs slow to prevent slipping or falling objects and it take 3-4 sec from one position to the next it a waste of time.
2sek scan 4 sek turn like this...

mfg milz
Xeon x5650@4ghz
Cam : USB2 CCD 1024x768 / USB3 1280x900
Laser : LC532-5-3-F(16x65) Focusable Green
Projector Acer X110P / Acer K132
dControl one David control box + Turntable + automatic texture lights
mooooom bathroom!!!!!!
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Re: High loadable turntable

Postby Curiousjeff » Tue Apr 28, 2015 11:38 am

Hello Walter,

What is the advantage of the planetary gear on the NEMA-17 Stepper Motor vs a regular NEMA 17 ?

Thanks.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: High loadable turntable

Postby WalterMo » Tue Apr 28, 2015 2:50 pm

Hi Jeff,
A motor with a gear gives much more power. And the acceleration and deceleration is finer. All these is specially necessary for a high loadable turntable.
The inertia of an e.g. 30 kg weight may not to be underestimated. Otherwise it could happen that the stepper motor „loses“ some steps.

Walter

Edit: Also have a look to this thread:
viewtopic.php?f=9&t=5895
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Re: High loadable turntable

Postby Curiousjeff » Tue Apr 28, 2015 4:46 pm

Thanks Walter,

I will follow your advice. I don't expect to go as high as 30 kg but I really want something smooth to avoid any risk of having the item fall.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: High loadable turntable

Postby Curiousjeff » Fri May 22, 2015 10:31 am

Hi Walter,

I have started purchasing the part to build the turntable.

Unfortunately, I have nearly no knowledge of electronics and I don't remember much of the laws of physics :?

I purchased the Arduino & the SaintSmart 3.5A driver board.

I am a little confused about what power supply to use. You mention earlier on a 9V. But on the diagram with the SainSmart you have a 12V.

What power supply do you recommend ? Does the SainSmart require a different power supply then the one for the Arduino ?

I am also ordering the planetary geared Nema 17. Can I use this turntable for all my scans (a few grams to 20 kilos) or do you recommend a different motor for a smaller turntable ?

Thanks for your help.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: High loadable turntable

Postby micr0 » Fri May 22, 2015 1:23 pm

Jeff,
Whats the gear ration of the gear set on the NEMA17?

The Arduino will except input voltage of 5v to 12v DC. The saint smart driver will except +5v to +24v in so you should be fine with a +9v power supply. The max rated current output of the Arduino however is 400ma IIRC so you will need to power the stepper board with it's own power supply or directly from one power supply that is rated for enough current for both components.

I power the Arduino controlling my turntable from the USB port of my laptop (it has a separate +9v barrel jack if I need it) and the steppers drivers have their own power supply.


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Re: High loadable turntable

Postby Curiousjeff » Fri May 22, 2015 4:54 pm

The stepper motor is the one recommended by Walter

Stepper motor with planetary gear:
http://nodna.de/nema-17-planetary-518-1-stepper-motor

Motor Type: Bipolar Stepper, Step Angle: 0.35°
Holding Torque: 18 kg·cm - Rated Torque: 18 kg·cm

Recommended Voltage: 12 V DC / Rated Current: 1.7 A

I had purchased a 9V / 1A power supply for the Arduino. I can get another one for the Sainsmart but would 9V / 1A be enough or should I get a power supply of 12 V / 1.7A as per the motor ?
Thanks,
Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: High loadable turntable

Postby micr0 » Fri May 22, 2015 8:03 pm

I have an adafruit stepper shield that will drive that motor. However that is with no load. If you have a turntable with 20Kg on it that little motor is going to be loaded accelerating and decelerating the load. that's where max current draw will be so having a separate power supply that can power the stepper driver will insure you donut let the smoke out of your arduino. That said get a 12v 2A supply. That Should be a pretty common wall wart. I think I have a bunch from an old cordless phone or rechargeable hand held vacuum.

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Re: High loadable turntable

Postby Curiousjeff » Fri May 22, 2015 8:09 pm

Great, thanks.

I'll use the 9V -1A for the Arduino and get a 12V - 2A for the shield.

I have a bag with plenty of old power supplies. It should not be hard to find.
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: High loadable turntable

Postby WalterMo » Fri May 22, 2015 8:18 pm

Hi Jeff,

Of course you can use the turntable for loads from 0 to 20kg, or more.

I would use a 12V power supply with the SaintSmart driver. As you mention some posts above: 12V is recommended for this NEMA-17 motor. Some power supplies have adjustable (in steps) output voltages. You don't need 2 supplies for Arduino and SaintSmart. Look on my circuit diagram: The Arduino is connected via the diode 1N4001 to its power input 'Vin'. The black female jack on the Arduino is left free.

It's not necessary to adjust (by means of the little switches on the SaintSmart board) a motor current >1A for each (!) of the two coils. A motor current of 0.5A or 1A is sufficient. So you need a power supply of 12V/1.5A or 12V/2.25A. Choose the possible output current a bit higher, the LCD display, the Arduino and the other electronics „need“ also current.

When using the Pololu A4988 I normally reduce the supply voltage. In so doing the little IC on the board will not be warmed up so much.

Remember: My Arduino code was written for ¼ micro stepping. The SaintSmart hasn't this. I had chosen ½ micro stepping.

Walter

Edit: The supply voltage for the Arduino uno is recommended to 7....12V. Each of the 2 diodes (1N4001 and 1N5400) will reduce the voltage by about 0.7V. So the Arduino will get circa 10.6V.
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Re: High loadable turntable

Postby Curiousjeff » Mon Jul 06, 2015 9:31 am

Hello Walter,

Some last (silly) questions before I assemble everything.

I have the Arduino, the planetary motor, the Sainsmart driver.

I am finalising the order from Conrad for the box, push buttons, etc...

a)
You mentionned above "power supply of 12V/1.5A or 12V/2.25A."

I have a 12V / 2A power supply. I guess this is ok to drive everything ?

b)
I cannot see very well on the photo the micro switch positions of the Sainsmart driver (I think SW1 = 1 / SW2 = 0 / SW3 = 0, but I am not sure about S1-S6)

c)
You mention a potentiometer 10K to adjust the contrast of the LCD (in a previous thread), but I don't see it on the photo of the box from the outside, but it seems to be there on the inside view (?)

Thanks.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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