CPH : What is exactly this magical number means? - Page 1
Forum section: electronics / general

author: olkipukki
author_rank: Frequent Contributor
timestamp: April 04, 2018, 11:53:04 pm
content: Is there standard definition for CPH numbers (worst-case, average etc.) or it up to manufacturer say - our machine can do, for example, 10000 CPH?

author: asmi
author_rank: Super Contributor
timestamp: April 05, 2018, 12:30:42 am
content: Components per hour?

author: olkipukki
author_rank: Frequent Contributor
timestamp: April 05, 2018, 12:32:56 am
content: Quote from: asmi on April 05, 2018, 12:30:42 amYep, but how they figured out their numbers?

author: mrpackethead
author_rank: Super Contributor
timestamp: April 05, 2018, 12:35:02 am
content: normally its marketing.. So it will be the absolyte max that can be acehived for a highly optimised job. My machines are rated at 14400 parts per hour. I typically get about 4000-5000 out of them, for 'real' jobs.

author: ovnr
author_rank: Frequent Contributor
timestamp: April 05, 2018, 12:40:29 am
content: I assume you mean for P&P machines?It's probably a real number, but it'll be best-case with a board tuned to the machine, and it probably only counts placement time (that is, the clock starts when fiducial acquisition and other pre-place tasks are done, and stops when the last component is down).For a normal single-nozzle P&P, you would probably have a single 0402 or 0603 component in a tight array with the board close to the feeders. For the fancier multi-nozzle machines, it'll be tuned for maximum pickup and placement speed for obvious reasons; I imagine some machines would perform best with one component reel per nozzle.Like any other badly defined measurement, it's not what you'll get out of the machine in the real world.

author: nisma
author_rank: Regular Contributor
timestamp: April 05, 2018, 07:12:09 pm
content: There exist different numbers.IPC9850 tryes to standarize this numbers, and there exist IPC CPH and vendor CPH.If you have only vendor CPH, lower that by 30% in order to estimate IPC CPH.As example if machine have 15kcph for resistors (laser centering) where the machine pick up6 resistors at the same time and place it near at same time, the IPC cph is 9kcph and for vision,it is 4,5kchp and fine pitch vision 1.8kcph.Real mixed cph is for determinated circuit and feeder loading is 7.5cph. The pcb have 48 components and the panel is compromised of 6x2 matrix.This are 576 components and 276 seconds for assembling, For the 26 Fiducials, each needing 0.6 seconds, is 15.6 seconds, and for panel unloading/loading, 22 seconds is needed.This is gives tact time of 336 seconds and approx 6.2kcph.Instead just as example, if the pcb is not panelized, the tact time is 70 seconds resulting at 2.5kcph performace.

author: Smallsmt
author_rank: Frequent Contributor
timestamp: April 06, 2018, 09:08:34 am
content: These are almost useless values given from many manufactures because it depends on so many parameters:- ratio between machine size and pcb size.- Head count- physical position of alignment / vision system- machine speed- vision speed- precision for placing parts- part sizeexample cycle using bottom vision is like this:- move to feeder position (speed and distance dependend)- pick up part using pick delay ( part and nozzle dependend)- move to vision system (speed and distance and part dependend)- vision alignment time (vison system speed and type dependend)- move to placement position (speed and distance and part dependend)- put part using put delay (part and precision dependend)example for flying vision cycle is like this:- move to feeder position (speed and distance dependend)- pick up part using pick delay (part and nozzle dependend)- move to placement position (speed and distance and part dependend)- vision alignment time (during movement)- put part using put delay (part and precision dependend)So if a single head machine only pick up resistor and place nearby maybe 4000 cph possible but this decrease to real world 2500cph because of different distances to move.If using vision on complex parts you receave maybe only 1000cph.On my VP-2800HP the average placement speed for my PCB using always vision on is between 1700 to 2700 cph.