Adding conveyer belt?

[Shai]

I'm just wrapping up the design of my PNP (long overdue) and I was wondering how hard would it be to add a conveyer belt if I wanted to put two side by side?

I'm thinking - 

1. 1x servo to lift/lower belt to lock pcbs in place.
2. 1x motor to push belt forward/back
3. sensor to detect pcb has arrived/removed

How hard would it be to implement this in OpenPNP to have two machines communicate together like so? Is it currently possible? Am I missing any other peripherals needed to make it happen?

[Matt Brocklehurst]

On commercial equipment you have a standard where every device has a READYIN and READYOUT connector

So readyin goes high when the machines idle, readyout goes high when the jobs complete.

You only want to move to the next stage when the next machine in the chain is ready (so its readyin is high)

No machine needs any other connection between them - they don't care if its an oven, or a stencil printer, or another identical placer

Virus-free. www.avast.com

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[Marek T.]

Hi Shai

1.usualy the belt is not lowered. At the place position the board is pushed up (air pen cylinders in my case). There is few vertical attenuators: mentioned one, some stopper pin to stop board where u want, and pins coming through the board to hold the board firmly and don't allow to change it's location during the assembling.

2. Conveyor has two directions (to load/unload from any side you want) and two speeds: fast for initial moving and slower just before the stopper - to don't hit to rapid onto stopper and don't move some parts on the board that were assembled on previous machine.

3. Sensors: is part put on conveyor to start loading, is part at mount position, is part on out position. You can't move the board if there is some one detected on another sensor (except mounting position wher board is held by pins). Bigger (longer x) machines have another position between load and mount, they can "park" one board more before the assembling.

So conveyor servis may be very simple if you do only manual loading/unloading, or need quite smart logic of need work together with other machines.

[ma...@makr.zone]

Hi

why not just use a normal stepper/belt (or whatever) driven axis?

I have that on my machine and I plan to add support to it in OpenPNP.

Driving it as an axis would simplify things immensly by reusing the same framework already there in OpenPNP, in movable actuators and in the (sub-) drivers. If you worry about an "endless" drive that would be easy to solve using GCode.

Having proper motion control, you have no problems with speeds, acceleration, reversing, backlash compensation, etc.

Plus for slow/simple machines it opens up new possibilities like the ones I talk about in the "Conveyor for the PCB" chapter here:
https://makr.zone/planning-the-work-area/117/

_Mark

[Marek T.]

Mark, this still the "problem" of sensors not driving. I.e. if you do disload the board you need read nonstop some sensor to get known where is the board. Incorporating this to Openpnp is trivial, there is not many to do. Everything depends if the machine is intended to work in-line with others or not, then you need eleminate a message about the placed parts canceling only. Few simple scripts do the job.

[Marek T.]

Imagine situation: our machine is doing the job and one board that we finshed before lays awaitin at the end on conveyor (still on our our machine). And you get info from the next machine that she finished her job and need the board. So you must continue own job but run conveyor to release this waiting-finished priorly board to the next machine.
So you must track nonstop signal from next machine.
And also from prevoius machine, she can anytime tell you that have the board to take from her. And you must decide whether you can or not, depend on you have a place to take it or not.
So as you see, if machine is eorking stand alone, it's simple. If in-line it gets little more complicated.

[ma...@makr.zone]

Hi Marek

I understand. I was not thinking about truly chained and automatic "assembly line" conveyor belts.

(But then, I also assume OpenPNP is missing other functionality to really support that).

_Mark

[Matt Brocklehurst]

Have you got a conveyor oven / stencil printer ? Not sure much benefit to a conveyor (disadvantage is less feeders) unless you have all other conveyor equipment?

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[Marek T.]

Hi Matt,

If it was to me: I have four pnp machines with conveyors but printer. Very often I divide one board to be assembled on more than one machine to speed up the process.

But I had no choice, I just have some old industrial machines with conveyors originally.

I also had an owen with conveyor but not used already due to low quality.

W dniu poniedziałek, 6 kwietnia 2020 14:08:19 UTC+2 użytkownik Matt Brocklehurst napisał:

Have you got a conveyor oven / stencil printer ? Not sure much benefit to a conveyor (disadvantage is less feeders) unless you have all other conveyor equipment?

On Mon, 6 Apr 2020 at 13:06, ma...@makr.zone <ma...@makr.zone> wrote:

Hi Marek

I understand. I was not thinking about truly chained and automatic "assembly line" conveyor belts.

(But then, I also assume OpenPNP is missing other functionality to really support that).

_Mark

Am 06.04.2020 um 13:40 schrieb Marek T.:

Imagine situation: our machine is doing the job and one board that we finshed before lays awaitin at the end on conveyor (still on our our machine). And you get info from the next machine that she finished her job and need the board. So you must continue own job but run conveyor to release this waiting-finished priorly board to the next machine.
So you must track nonstop signal from next machine.
And also from prevoius machine, she can anytime tell you that have the board to take from her. And you must decide whether you can or not, depend on you have a place to take it or not.
So as you see, if machine is eorking stand alone, it's simple. If in-line it gets little more complicated.

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[Jarosław Karwik]

I have been working on my own controller ( for my upgrade of Philips Csm 66 ).

The controller will support also conveyors - even in fully automatic mode. The connection to OpenPnp would be with subdriver and gcodes ( just to turn it on in proper mode).

My system contains 3 proximity sensors, pneumatic bumper, pneumatic support for position/support pins and motor ( I have replaced original AC motor with high torque stepper to drive belts directly).

[Shai]

The reason I wanted to add it is because my PNP design doesn't have enough feeders for some of the boards I want to make. So I was thinking of putting two side by side rather than swapping feeders and run a split job on both. But as I gather from the comments, this is not yet possible with a conveyer, I would have to manually move the board.

[Jarosław Karwik]

Well, you may not be able to do 100% auto, but the worst case would be to manuallu activate Actuator or two to activate belt engines between machines. Maybe it could be done wit scripts ...

pon., 6 kwi 2020, 16:46 użytkownik Shai <shai...@gmail.com> napisał:

The reason I wanted to add it is because my PNP design doesn't have enough feeders for some of the boards I want to make. So I was thinking of putting two side by side rather than swapping feeders and run a split job on both. But as I gather from the comments, this is not yet possible with a conveyer, I would have to manually move the board.

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[John Plocher]

With a conveyer table or oven or ... on each end, the READY-IN and -OUT signals work well in both manual and auto modes:

My manual workflow with my SMT550 (non-openPnP) is

Put a newly solder-pasted board on the IN-conveyer,  press its "pass" button to make its READY-OUT go true

Press "load-board" on the machine's controller software application

the READY-IN line goes true, the conveyers spin, pcbs move between segments, the board loads into the pnp, when it reaches the right place in the machine, it slows and a pneumatic pin raises to stop the board.  Once stopped, the belt stops, another pneumatic piston clamps the board in place and the stopping-pin drops back down - and READY-IN goes false.

Press Place Job, and the machine runs

Press "unload-board" and the piston holding the board in place drops out, the conveyer runs, and when the board nears the machine exit, the READY-OUT signal goes true and the exiting conveyer table starts up...

For automatic operation, all the manual button presses above go away and things start up as soon as the input conveyer says "READY-OUT"...

Each segment (input table, pnp-machine, output table,...) has optical -in, -middle and -out sensors with a self-managed timeout of 5 to 10 seconds in case of a jam or missing board; if the sensors don't detect something, their belts stop.

   -John

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