Acctek AKM1212 CNC Router

This forum is dedicated to retrofitting existing CNC Machines with Buildbotics Controllers.
Forum rules
Use of profanity is prohibited.
Gambling is prohibited.
Sexual or pornographic material is prohibited.
Illegal activities of any kind are prohibited.
The moderator reserves the right to deny or delete any content without notice.
Post Reply
User avatar
CarbonThreeSixty
Posts: 4
Joined: Fri Mar 16, 2018 7:00 am

Acctek AKM1212 CNC Router

Post by CarbonThreeSixty » Tue Mar 27, 2018 5:08 am

Hi Everyone,

We're in the process of upgrading the controller on our Accetek AKM1212 from a Mach3 to our Buildbotics controller. I'll probably post a lot of questions, information and photos over the next few weeks!

First question - our y-axis is a twin motor arrangement with two motor drives currently. In the documents you mention "The fourth driver can also be synchronized to drive a single axis with two motors."

Any more info on how to do this?

Thanks,

Will

User avatar
Doug
Posts: 239
Joined: Fri Feb 02, 2018 4:56 pm

Re: Acctek AKM1212 CNC Router

Post by Doug » Tue Mar 27, 2018 9:22 am

Sounds like a fun project.

There are three ways that you can hook up two motors for a single axis.
1. Wire the motors in parallel from a single port. This method only works if the motor rating for the individual motors is 3 amps or less because the total current available from a single driver port is limited to 6 amps. This method does not use the fourth port. This method does not reduce the maximum velocity because the full power supply voltage is supplied to each motor.
2. Wire the motors in series from a single port. This method allows you to use motors that are rated up to 6 amps. The disadvantage is that the motors will split the voltage drop from the output of the port. This will reduce the maximum velocity.
3. Wire the motors from separate ports. This method allows using motors that are rated up to 6 amps and does not split the voltage drop between the motors. Therefore, the maximum velocity is not reduced. The disadvantage is that the fourth port is no longer available for some other use. You can configure this by assigning two motor ports to the same axis in the motor configuration screen. For instance, if the y-axis has two drives, you would probably assign motors 1 and 3 to the Y axis.

Depending on the type of drive being used and how the motors are connected to the drive, the motors may need to turn in opposite directions. If this is the case, you can cause the motors to turn in opposite directions in software by checking the "reverse" box for one of the motors in the motor configuration page. Alternatively, you can simply reverse one of the motor pairs (but not both) on one of the motors when you wire it up.

If you can provide more details on your system, I can probably make a few more suggestions. Items of interest are:
* The make and model of the stepper motors.
* The voltage and current rating of the DC power supply supplying the Buildbotics Controller
* The type of drive system. Ball screw, lead screw, pinion, etc...
* The type of spindle (and VFD if used).

I'm really excited to see you system work. Please let us know how it goes.

User avatar
CarbonThreeSixty
Posts: 4
Joined: Fri Mar 16, 2018 7:00 am

Re: Acctek AKM1212 CNC Router

Post by CarbonThreeSixty » Wed Mar 28, 2018 7:54 am

Hi Doug,

Should be great once we're up and running - good news; X, Y and Z axis are moving!

Make and Model of Stepper Motors - Type 86BYG 450B-79-A50-J5 (5.0A 1.8º)
Voltage & Current Rating of DC Power Supply - Mean Well GST280A-C6P 24V Power Adapter; as bundled with our controller.
Type of Drive system - Pinion
Type of Spindle - Changzhou Changlong Motor Co. Ltd 3kW Water Cooled Model Number GDZ100-3 http://www.czclmtor.com/3kw_er20_400hz_ ... 15407.html
Type of VFD - Zhejiang New Folinn Electric Co Ltd DBZ280B003.7L4DK

We've not got the spindle running yet - I think it'll be a matter of configuring our VFD to accept RS485.

Cheers, W

User avatar
Doug
Posts: 239
Joined: Fri Feb 02, 2018 4:56 pm

Re: Acctek AKM1212 CNC Router

Post by Doug » Wed Mar 28, 2018 9:15 am

I'm glad your motors are all moving. How did you end up connecting the axis that is driven with two motors?

The spindle could pose a problem. Communicating via RS485 is only part of the issue. The exact commands are specific to each spindle. Unless, it uses the same protocol as the Huanyang spindles, it will require some additional software to make it communicate.

The good news is that Joe is currently working an a more sophisticated RS485 interface that should be able to communicate with many different RS485 spindles. If you can provide a manual for the spindle, we should be able to help get it going.

User avatar
CarbonThreeSixty
Posts: 4
Joined: Fri Mar 16, 2018 7:00 am

Re: Acctek AKM1212 CNC Router

Post by CarbonThreeSixty » Thu Mar 29, 2018 12:34 am

Hi Doug - we used the 4th axis port and synchronised. We don't currently envisage needing an A-axis, so should be fine.

I did managed to overload our power supply yesterday, but the thermal cutout reset after a while. I think we possibly need a higher rated power supply (obv not more than 20amps!)

Is it possible for the buildbotics controller to supply signals to our existing set of 4off Leadshine M860 motor drivers or does that defy the point of the buildbotics box? They're running at 70V and can provide a lot more power.

W

User avatar
Doug
Posts: 239
Joined: Fri Feb 02, 2018 4:56 pm

Re: Acctek AKM1212 CNC Router

Post by Doug » Thu Mar 29, 2018 1:12 pm

The Buildbotics Controller cannot supply signals to the Leadshine drivers.

Did your motors appear to stall before the power supply shut down? It is possible that your Mean Well power supply did not cut out due to overcurrent. When motors stall, the inertia of the motor is dissipated by feeding current back into the controller. This current charges the caps inside the driver. If the caps charge to a value that is more than 1 volt greater than the 'nominal' input voltage, the controller turns on a shunt circuit and attempts to dissipate the excess energy through a 10 ohm resistor. If the inertia is too great, the caps will continue to charge while the energy is dissipated. The mean well power supply has a voltage threshold as well and will turn itself off as you described when this happens. We have found these GS280A-24 adapters to be quite sensitive to this situation.

You might want to try something like this:
https://power.sager.com/se-350-36-25266 ... fyEALw_wcB

This 36Volt power supply will provide torque at higher speeds than the 24 volt supply and hopefully it will be more forgiving in the face of a motor stall.

Post Reply