Selective Soldering Robot Conversion to Mach3 and Smooth Stepper

This build thread is of a Fisnar Selective Soldering Robot.

The plan is to convert from its propriety control to the Mach3 CNC control Software and a SmoothStepper.

The soldering robot is pictured in the attached image. It was purchased as a 2nd hand machine and pulled out of a production environment. The Robot is basically a 3 Axis X/Y/Z platform base with an automated soldering head module mounted to the gantry. As the soldering head is a separate module, it has it's own teach pendent which is used to program the automated soldering cycles in it.

Currently the machine is programmed in 2 parts. First, the head is programmed with all the different soldering profiles, including

• joint pre-heat,
• the amount of solder feed,
• rotation of the head,
• the soldering duration etc.

These different profiles are called Blocks.

The 2nd part is to program the base X/Y/Z movements with the other pendant. You move the head to a point, then select the soldering block you want to execute. You do this for every solder point. It works OK but is very tedious to program.

When the robot is soldering, the soldering tip moves down by a pneumatic actuator. The air pressure controls the contact force. You need to position the head so that the iron contacts both surfaces of the joint precisely .

The soldering head has 30 different soldering profiles. Each profile has 9 or so different parameters that define the soldering cycle. The base unit selects the profile it wants and tells it to do it. Once it receives the acknowledgement back, it carries on.

The video below shows the machine operating under the existing inbuilt software.

Selective soldering through hole components - YouTube

The soldering unit that attaches to the gantry along with its controller and programming pendant will be used "as is". In addition to the pendant the soldering unit has a external control cable that plugs into the main base.

In brief, the control of the soldering module via the external interface is

• 5 lines are used to select which of the 30 sdoldering blocks (pre-programmed soldering operation) is to be performed
• 1 line to sent the "Start" pulse to the unit.
• 1 line to receive the end pulse once the soldering operation is complete
• 1 line to receive an error signal from the unit.

So, to solder a joint, the base moves the gantry to the correct X,Y,Z position, then the Soldering unit is commanded to perform one of the 30 soldering cycles. All very simple.

For the conversion, I plan to use Mach3 for the CNC control software and a SmoothStepper. The reason for the SmoothStepper is that it has the equivalent of two buffered parallel ports on it. I plan to use port 1 to control the X,Y,Z Base. So that's the 3 axis stepper drivers, the 3 axis home switches, and the halt and start switches. The 2nd parallel port will be used to control the Soldering head unit. By using the SmoothStepper, the connection from the PC to the robot will be a single USB cable.

The Shuttle PC I'm using can be seen below.

As to the computer, at this stage I'm planning to use an all-in-one Shuttle X50 V2 15" Panel PC. It has;

• four USB ports,
• Ethernet,
• 15.6" touch screen
• VESA Mount
• Serial Port
• NO Parallel Port

The only Issue I see is that it has an Atom Intel® D510 dual-core processor, so hopefully it will work with Mach3. I plan to have it mounted on a stand adjacent to the main Unit. Being a touch screen, I may be able to get away from the Keyboard and mouse. Not sure if that is going to be possible but we will see.

Images of the electronics are attached.

Below is the base of the unit containing the electronics. The three stepper dirivers can clearly by seen, along with the 24Vdc switch mode power supply.

Visible are two PCBs. In fact there is another sitting under the one on the right.

The PCB on the left is primarily the interface board for control of the external Units such as my soldering unit. All of the output lines are switches by relays. The external units are connected by a 50 pin centronics connector. THE connector to the left is for the base unit's teach pendant. I will be replacing this board with my own that will interface to the Smooth Stepper Port two.

The boards to the left contain the processor, memory, RS232, etc. These will be replaced by a small breakout board that will interface to the SmoothStepper port 1.

I plan to use the existing wiring cables, so my boards will been to have matching connectors. I want to just plug in as much as possible without cutting anything.

As can be seen the base is very solid and cast. The Y axis stepper is clearly visible. Initially my plan was to replace the stepper drivers with a Geckodrive G540 4 axis stepper drive. On closer inspection of the motors, I discovered that they were Vexta 5-phase motors and are no compatible with the Geckodrive G540 bi-polar drive.

I then contemplated replacing the motors as they seemed to be size 23 steppers. I removed one and did a trial fit of one of my motors. What I found was that the aligning boss on the Vextra motors is fractionally smaller than the standard size 23 boss. Also the bolt hole mounting pattern was different.

In the end I decided that it was simpler to use the existing Vextra 5-phase stepper drivers until I discovered that they take a Clockwise and Counter Clockwise input, rather than the more common Step and Direction inputs that Mach3 generates. so nothing is ever as simple as it first seems.

So now my plan is to put a set of Step/Dir to CW/CCW converters on the driver breakout board. I'll use a separate Microchip PIC processor for each axis to do this. I could use discrete logic to do this but I also want to use the PIC to improve the homing accuracy.

The Vextra drives (1/2 steppers) have a sync output that is present every 20 steps. I plan to AND this with the home switch input before sending it to Mach3.

This will improve the repeatability of the home switches, as once the switch is activated, the axis will continue to move until the drive activates the sync signal. So even though the activation of the optical home switch will have some variability, it will be corrected by the sync output which is absolute. I used this technique on my TurboTaig board and it works very well.

I've designed the Step/Dir to CW/CCW board for converting the signals from Mach3 to that required by the Vexta half stepper drives. Additionally, the board also receives and opto-isolates the home switch inputs.

I don't usually bother with homes switches on my machines as most of the work on them is one offs and I normally just manually set the home or reference position to the work piece once it is clamped down. This machine is different, it is a production machine. Jigs are fitted to the machine and boards to be soldered are located into the jigs. Once set up, I can place the jig and pcb into the machine, home it and then just cycle start.

I designed the circuit, laid out the pcb and had the board house produce a batch of them. As you can see it is a lot smaller than the PCB it is replacing. To be fair, the original pcb was part of a machine that was a complete stand-alone system.


Below is an image of the populated PCB. I stole the connectors off the original board as I was too lazy to source them. The only mistake was I did not put enough separation between the connectors for the three axis drives so plugging in the cables is a tight squeeze. If you look closely, you can see that the microprocessors are labelled DC-03V3, which are the pre-programmed ones for the DigiSpeed controller. I didn't have any spare ones around, so I just grabbed them from the tube off the pick and place machine and re-programmed them.

It wasn't a difficult layout, but it is always satisfying when there are no mods on the pcb. The only change I had to make was to replace the 2.7K opto-led bias resistor with a lower value one.

It worked first time which was probably first in itself for me. Looking at the manual for the machine, the accuracy and repeatability for the X and Y axis is specified at 0.05mm.The Z axis is 0.024mm.

So, from that I knew that the base units for the machine are likely to be mm, and the steps/mm is likely to be 1/.05 = 20

I configured Mach3 to this, then did a quick test and it appears to be correct according to a ruler. The manual also specified that the maximum speed was 500mm/s. I cut the air with the roadrunner.tap file running at 4000mm/min. It seemed to handle that without any problems.

I did notice that the motion is a lot smoother than it used to be. I put this down to the step generator on the original set-up being a lot coarser than that being produced by Mach3 and the SmoothStepper.

The image below shows the new pcb and the smoothstepper inside the base.

The next step is to start on the Solder head interface board. It uses signal relays for the outputs and opto-isolators for the inputs.All of the signals enter/exit through a 50-pin Centronics connector.

Once thing I did release when starting to look at the H-02 board , is that I need nine relay outputs, and 11 opto inputs for the expansion port. Then there is a 4 bit single digit program selector switch, cycle start button on the front panel.

I like to use the selector switch on the machine to select and load the GCode program. Not sure how easy it is to do this, but it should be possible.

Looking at the I/O requirements, a single 2nd port is not going to be enough to deal with all these signals.

The solution I'm now leaning towards is to use the Ethernet Version of the Smooth Stepper. It has the equivalent of three parallel ports.

Very cool! Thanks for posting. I'm jealous of your soldering machine (even though I farm out most soldering these days) it's still a really cool machine to have in-house. :)

Hi all,

Well I've managed to find some time to get back to the Mach3 conversion of my Soldering Robot and have made some real progress.

I tested the H-02 I/O interface board I made to interface to the soldering head. The board consists of 17 opto-isolated inputs and 9 relay outputs. Obviously this is too much I/O for a single parallel port and requires 2 ports to manage the I/O.

I already have port 1 dedicated to the H-01 stepper drive board that manages the 3 axis drives plus the limit/home switch inputs. As I needed three ports to deal with this machine the obvious choice was to use the Ethernet SmoothStepper which has 3 parallel ports on it.

Port 2 is used to drive the 9 relays plus accept the inputs from the base switches, etc
Port 3 has D2-D9 configured as inputs and deals primarily with the inputs from the soldering head.

I'm really pleased with this setup, and I don't think there are many other solutions to this problem that would be as economical as the Ethernet SmoothStepper.

Soldering Cycle selected Tool Changes

As previously described, the soldering head has its own pendant that is used to program the parameters for the 31 different soldering cycles called blocks. The block to be used is selected by 5 output lines that represent the binary value of the selected block.

I've created a M6Start Tool change macro that I use to select the block number. Tool 1 will select Block 1, Tool 2 selects Block 2, etc. The macro is listed below.

Because the soldering iron tip does not align with the C axis rotation, I'll need to apply some X/Y offsets so that the tip is correctly positioned for the soldering joint location.
My current plan is to see if I can use the tool wear and Tool height values in the tool table, using them to set the X/Y values in a G52 X Y offset which will occur in the Tool change macro.

Code:

---

'              Fisnar Soldering ToolChange Macro
'              --------------------------------
'
'The tool number is used to select the soldering cycle that the head is to
'perform. There are 31 different soldering cycles that can be chosen. The
'parameters for each cycle needs to be programmed into the head by a separate
'pendant that comes with the head. The Toolchange macro then just selects which 'cycle is selected.

'Mach3 outs used to select the 5 bits defining the cycle number. Block1 is the LSB
const BLOCK1  =  OUTPUT2
const BLOCK2  =  OUTPUT3
const BLOCK3  =  OUTPUT4
const BLOCK4  =  OUTPUT5
const BLOCK5  =  OUTPUT6
 

'Get the new tool number
 tool = GetSelectedTool()
 
'Deativate all outputs
DeActivateSignal(BLOCK1)
DeActivateSignal(BLOCK2)
DeActivateSignal(BLOCK3)
DeActivateSignal(BLOCK4)
DeActivateSignal(BLOCK5)

'Turn on outputs as required for the selected tool
select case tool
  case 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31
    ActivateSignal(BLOCK1)
end select

select case tool
  case 2,3,6,7,10,11,14,15,18,19,22,23,26,27,30,31
    ActivateSignal(BLOCK2)
end select

select case tool
  case 4,5,6,7,12,13,14,15,20,21,22,23,28,29,30,31
    ActivateSignal(BLOCK3)
end select

select case tool
  case 8,9,10,11,12,13,14,15,24,25,26,27,28,29,30,31
    ActivateSignal(BLOCK4)
end select

select case tool
  case 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
    ActivateSignal(BLOCK5)
end select
 
'Set the current tool to the new one
SetCurrentTool( tool )

---

Solder Cycle using G82 drill with Dwell command.

The locations to be soldered come from the Excellon PCB drill files that are produced as part of the pcb artwork file set.

These files basically have a drill tool number and a list of X/Y locations where the holes are to be drilled. I'll pass this through sheetcam to turn it into GCode suitable for Mach3.

The different hole sizes are an initial indication of the soldering block required. For instance, a 0.9mm hole is likely to be a 0.1" header as found on a jumper terminal. A 1.5mm hole is likely to be a strip header for a 5.08mm terminal block, etc.

For each of the different soldering cycles, say a cycle for a 0.1" header, there needs to be 4 cycles defined, 1 for each of the four quadrants that the iron will be approaching the joint at, 0, 90, 180, 270 degrees. Each one of these needs to be a different soldering block in the head. I will need to manually edit the Gcode file to select the most appropriate angle (block) to approach the joint from.

I was trying to work out a way to interface Gcode and the soldering head so that the head would move to an X/Y position, initiate a solder cycle, wait for it to finish, then move to the next position. I was looking at calling a Macro for each soldering position.

Terry Parker, who knows more about Mach3 and G-Code programming than most, suggested a method that I should try using the G82 drill with dwell command.
G82 drills to a depth then dwells at the bottom of the hole for a defined period. The problem with this is that I didn't want to hang around with a dwell to cover the longest soldering cycle.
Terry then he suggested that I could try cancelling the dwell when the soldering cycle finished, causing the G82 to move to the next drill location.

To be honest, I was sceptical, but decided it was worth a go. It took a while to sort out but it ended up being quite simple and very effective.

It really highlights the versatility of Mach3.

My G-Code file I used for Testing is Below. As can be seen first Tool (solder cycle) 2 is selected. The G82 drill depth is Z10 with is a zero depth as the Z is already at 10mm. The retract is also at 10mm and the dwell period is 10S. The program solders at 4 locations, then changes to tool 30 and solders another 4 location.
All very straight forward to code. The Test code is;

Code:

---

F2000
M6T2
G0 Z10
G0 X0 Y50
G82 X0 Y50 Z10 R10 P10
X50
X100
X200
G80
M6T30
G82 X0 Y90 Z10 R10 P10
X50
X100
X200
G80
M30

---

The 'miracle' occurs in the macropump macro which is continuously run at a 10Hz rate.
The macropump is written basically as a state machine where it;

1. waits for the dwell to appear
2. then starts the soldering cycle
3. waits for the soldering cycle to end
4. then cancels the dwell.

There are also a couple of checks;

1. The program is aborted if the solder head is not ready to start a cycle.
2. The program is aborted if the solder cycle is not completed with the dwell period (10s).

The Macropump is listed below;

Code:

---

'              Fisnar Soldering Robot Macropump
'              --------------------------------
'
'Soldering is performed by using the G82 drill cycle with dwell.

'The soldering head has an Standby output that indicates that the head is
'idle and ready for use. This signal becomes inactive if the head is
'executing a soldering block cycle or if it faults. The head also has a START
'input that initiates a Soldering block Cycle.

'The head has 31 Soldering block cycles. The M6start toolchange macro is used
'to select the soldering block to be used.
'
'Basically this macropump monitors the Dwell LED. If the dwell is active,
'the macro initiates the soldering cycle by activating the SOLDER_START
'output.  The sleep delay is important as the output activates a relay and the soldering head takes a little time to deactivate the SOLDER_READY signal
'
'It then waits for the cycle to end by monitoring the SOLDER_READY
'input. When this input goes active, the macro cancels the Dwell and the G82
'moves to the next drill (solder) location and it all starts again.
'
'If the Dwell expires and the soldering cycle has not completed, the program
'is aborted and an estop is generated.



'Solder Cycle Start output
const SOLDER_START        = OUTPUT1

'Solder head Standby input
const SOLDER_READY        = INPUT1

'User LED to indicate when a solder cycle is being executed
Const SOLDER_IN_PROGRESS  = 1050

'System LED indicating a dwell is in progress
Const DWELL_LED          = 813

'System Button used to cancel the current dwell
Const CANCEL_DWELL_BUTTON = 297

'System Button used to abort the program
Const RESET_BUTTON        = 1021


 
'Soldering not in progress so do it
If GetOemLED(DWELL_LED) Then
    If  ( GetUserLED (SOLDER_IN_PROGRESS) =0 ) Then
        If IsActive(SOLDER_READY)  Then
            SetUserLED (SOLDER_IN_PROGRESS,1)
            ActivateSignal(SOLDER_START)
            sleep (500)
        Else
            'If head not Ready then Abort program
            Message "ERROR Solder Head Not Ready..."
            DoOemButton(RESET_BUTTON)
        End If
    End If
End If

'Soldering is in progress so wait to finish
If (GetOemLED(DWELL_LED) And GetUserLED (SOLDER_IN_PROGRESS) ) Then
    If  (IsActive(SOLDER_READY)) Then
'        Message "Solder Is Done"
        DeactivateSignal(SOLDER_START)
        DoOemButton(CANCEL_DWELL_BUTTON)
        SetUserLED (SOLDER_IN_PROGRESS,0)
    End If
End If
     
'ERROR Soldering cycle failed to finish in time
If (GetUserLED (SOLDER_IN_PROGRESS) And Not GetOemLED(DWELL_LED)) Then     
    Message "ERROR Solder Cycle TIMEOUT..."
    SetUserLED (SOLDER_IN_PROGRESS,0)
    DoOemButton(RESET_BUTTON)
End If

---

Getting the Macropump and the G82 to work is a big milestone as it has proved that I'm going to get this robot to work under Mach3. There is still a lot to do as in the end I want to automate its use and minimise the screen/mouse/keyboard as much as possible.

The robot has a 16 position program selector switch. I plan to use this to select the G-Code program to use. Basically this will be done via the Start switch on the Robot base.

When the switch is pushed it will;

1. First Check if the machine has been referenced. If not or if it has just come out of Reset is will home the axis and do nothing else.
2. If pressed and the machine is referenced and the value of the program selector switch (1-16) does matches the loaded program, the new program will be loaded and nothing else will be done.
3. If the switch is pressed, and the machine is referenced and the correct program is loaded, the program will be run.

So once Mach3 is started, I should be able to run it off the start button and program selector switch. That's the plan at the moment.

Then, I need to do a new screen set to match the functionality of the solder robot.

The next step will be to generate a 'real' G-Code file for the ModIO or MB-02V6 breakout board and proved that it can solder up the board.

I'm really pleased how this is turning out and I quite sure I could not have done it as cheaply and easily with software other than Mach3 and hardware other than the Ethernet SmoothStepper.

Cheers,

Peter

Hi,

I made some more progress over the weekend. I fully tested both of my boards and reassembled the machine.

I also mounted the swing arm onto the side of the machine to hold the all-in-one touch screen computer. The sides of the static gantry are cast aluminium. after removing the sheet metal cover, it was clear that I could mount the swing arm at the top of the gantry side. I drilled and tapped holes for M6x1 cap screws.

With the machine reassembled, a quick test was done to ensure that all was plugged correctly. At this stage I now have a machine that is under control of Mach3 and is capable of soldering boards.

The first image shows the layout of the components in the base. As can be seen, there is a lot of room left over.

The 2nd image shows the machine about to be placed onto the base

The 3rd image show the top of the gantry side where the swing arm is to be mounted.

The final image shows the complete and assembled machine.

Quote:

---

Originally Posted by phomann

Hi,

I made some more progress over the weekend. I fully tested both of my boards and reassembled the machine.
I also mounted the swing arm onto the side of the machine to hold the all-in-one touch screen computer. The sides of the static gantry are cast aluminium. after removing the sheet metal cover, it was clear that I could mount the swing arm at the top of the gantry side. I drilled and tapped holes for M6x1 cap screws.
With the machine reassembled, a quick test was done to ensure that all was plugged correctly. At this stage I now have a machine that is under control of Mach3 and is capable of soldering boards.

The first image shows the layout of the components in the base. As can be seen, there is a lot of room left over.
The 2nd image shows the machine about to be placed onto the base
The 3rd image show the top of the gantry side where the swing arm is to be mounted.
The final image shows the complete and assembled machine.

---

Excellent progress. I've waited almost two years for some movement on this.

I have the bigger brother to that one, the IJ750-LN. Would you let me buy your firmware/Gerber files to build my own boards? I can DIY a layout from a schematic. Anything you can offer to me would be fantastic. My application is for drilling/milling light plastics.

Hi,

When I got the boards made up they have a minimum order qty, so I have about 8-10 spare boards.

Basically, you would need to confirm that your machine has the same Vextra 5 phase stepper drivers and ribbon cable connectors on it. if so then one of my boards would be the easiest solution.

Cheers,

Peter.

Nice one peter. Makes me want to get started on my A1 Roland plotter conversion to SMD pick and place, after I've finished current CNC project.
I think the hard part is the solder paste applicator? Need to ruggedise the Z axis a bit, as I threw the pens away.
I suppose the Syil SX3 mill would be better as a solder paste applicator.

Quote:

---

Originally Posted by phomann

Hi,

When I got the boards made up they have a minimum order qty, so I have about 8-10 spare boards.

Basically, you would need to confirm that your machine has the same Vextra 5 phase stepper drivers and ribbon cable connectors on it. if so then one of my boards would be the easiest solution.

Cheers,

Peter.

---

They are the Vexta 5 phase boards with a slightly different layout configuration, but the same number of pins per connector. I would be extraordinarily thankful if you would sell them to me - no strings attached. I am good at reverse engineering, but have many irons in the fire that keep this CNC project at bay. Therefore, while I could do the same kind of work, I am in a better position to pay you for the work you have done.

I will send you a PM with my details.

Regards,
Aaron Hammett
Envision Electronics Design, LLC

Hi Aaron,

I can provide the blank pcbs only (with the 3 stepper microprocessors installed and programmed). Like you I have so much going on that I don't have the time to assemble the boards for you.

You only need to see how long this project is taking to see how little spare time I have.

I'll contact you off-forum via email.

Cheers,

Peter

Quote:

---

Originally Posted by phomann

Hi Aaron,

I can provide the blank pcbs only (with the 3 stepper microprocessors installed and programmed). Like you I have so much going on that I don't have the time to assemble the boards for you.

You only need to see how long this project is taking to see how little spare time I have.

I'll contact you off-forum via email.

Cheers,

Peter

---

No problem at all. I feel very lucky to have blank boards and will happily do all the remaining legwork.

I haven't heard anything yet? Spring is just around the corner which means I can start getting some of these projects out of the way.

Ok, I guess I'm on my own again. I don't mean to rush, but I don't think an quick reply should take three weeks. I'm not asking for spoon feeding, just an amount I can send to get bare boards and a simple list of parts. $100? $200? Doesn't matter.

Three months and no replies at all... :(

Bumping in case Mr Hohmann sees this.

Almost a full year has transpired and I never heard from Peter Hohmann again after a single email that said "I'll get you something next week" - yeah, right.

I can't help but think you treat your customers this way. After all, I offered to pay a reasonable or unreasonable amount. I didn't care if it was buggy or not perfect. I wanted to pay for the chance to get started. Since my first reply, I've had a second child and have even less time to spend on my toys. Thus, I'm willing to spend even more money to get it working. But if you're not in the business of making money, then I'll take my business elsewhere.