Charmhigh CHMT48VB Zeroing Question - Page 1
Forum section: electronics / general

author: TechnoV
author_rank: Newbie
timestamp: February 10, 2019, 05:05:31 pm
content: Hello. I recently purchased a Charmhigh CHMT48VB pick and place machine, and am in the middle of programming my second PCB. I'm happy with the way the machine works on the first board. I have a little trouble understanding the customer support from Charmhigh since their English is not too good. Not only back to me, but also I don't think they fully understand my questions. The manual likewise is a little tough to understand.I'm generally confused about how the board calibration is supposed to work, and wonder if one of you can explain it to me. Once you enter a program, or read a CSV file, then go to the "Pcb calibrate" screen, the system chooses two components to calibrate, one in the upper left, and the other in the lower right. You go to each one manually and can bombsite the points.However, sometimes the machine picks points that it can't find with the vision system. Anyone know how to change the points the system chooses? Maybe edit the dpv file? Alternatively there are Mark points, but the factory told me not to use those.On a bigger scale, how is the pcb calibration used? Is it only done manually one time when you write the program? Does the system check those points when it starts a run? Is it there to translate the xy offsets of the PCB components to machine components?Any help would be appreciated.

author: pysco68
author_rank: Contributor
timestamp: February 19, 2019, 03:14:44 pm
content: Hi TechnoV,I own a CHMT560P4, so the big big brother of the 48VB, but I think the control software is identical.The system works in two "stages". First you define the known locationsof the "visual" centerof the geometric features (e.g. pads or fiducials) on the pcb, relative to origin of the machine.By default this should be the front left corner where the PCB sits in the holding rail. This is done by editing the dpv file either by hand, on the machine or in Charmhigh's desktop software.The second stage is to teach the vision system the Eigenvalue of the geometric feature. Basically you run the vision camera over the board until the vision system "locks" on the mark (pad/fiducial) you're targetting. If for some reason the center mark has an offset, you may need to account for that in the coordinates you set before.The actual scanning/checking of the marks finally happens when you start a run.So, what can go wrong:- by experience every soldermask-color / finish combination does not work equally well as Charmhigh didn't implement RGB top-lightning so contrast may be an issue.- the vision system is VERY sensitive to light scatter. I think this is worse on your machine as it has no covers at all. On my 560P4 I have to work with closed lid when using the computer vision as I have an lamp on the ceiling that confuses the up-facing camera. During the sunrise in summer I have to close the window blinds in my office to get it to work reliably. So watch out for that.Generally we've had most success by using the 3-points method with 1mm fiducials having a 1mm solder mask gap around them. Don't know why they told you not to use it.

author: Ribster
author_rank: Frequent Contributor
timestamp: April 17, 2019, 09:44:16 am
content: Hey Psyco.I am looking to buy a CHMT560P4.What are your overall experiences with it ?

author: pysco68
author_rank: Contributor
timestamp: May 14, 2019, 07:04:08 am
content: Hello Ribster,sorry for the really late answer. The CHMT560P4 is great in my books with most things working "as expected" out of the box.We've ended up writing our own PC Software tooling for the machine as the provided one - while functional - is really clumsy.I can definitely recommend the feeders they sell with the machine, which are on par with the "real deal" from Yamaha IMO.The only litte disapointement was that the machine had a little bit of rust out of the box (a fixture for the actuall feeder bed, nothing dramatic, but a surprise).If this is your first P&P Machine at all:- you always have to few feeders, so buy plenty of each size- nozzle size matters, especially for smaller components (0402 and below) so be sure to ask them to send you the right ones- if the vision system behaves weirdly, close the machine's lid. Overhead lights make it freak out

author: Ribster
author_rank: Frequent Contributor
timestamp: May 14, 2019, 10:09:21 am
content: Hey PsycoYeah no worries. I appreciate the reply.Im currently deciding to go with the CHMT560P4 or the SMT660.As the CHMT560P4 is a benchtop model, i can make a dedicated rolling cart where i can put the feeders in.Price is also lower, so i might go with that one.I'm planning in writing my own stock management software as a web interface.There i can upload all the BOM's for my designs, coming from my own database library in altium.I'll make unique QR codes on the feeders, so i can have a decent fast setup time and management of everything.I'd be interested how you set everything up tho. So if you have more information to share about your tool, please share.As far as feeders goes, i'm looking to just get the CL feeders, no electrical ones.What configuration do u recommend ? My plan is to get everything on a dedicated feeder to minimize my setup cost.Although i don't want to buy feeders that i don't use, if i do use them i will not hesitate.How did you order it ? I got a contact via mail: Michelle Zhang, directly got a quote.You also have Kimi right over at aliexpress.The shipping via Michelle was going to take a month, while she gave very good feeder rates.I think the aliexpress route will be more expensive, but it's more secure that way financially wise.There kimi said they will use TNT (iirc), and they help importing the thing.Thanks for the input! Greatly appreciated!

author: NorthGuy
author_rank: Super Contributor
timestamp: May 14, 2019, 02:55:02 pm
content: Quote from: pysco68 on May 14, 2019, 07:04:08 amDid they give you API to interface the machine?

author: pysco68
author_rank: Contributor
timestamp: May 24, 2019, 06:21:31 am
content: @NorthGuy: I basically reverse engineered their file format. So it's still the same workflow of making the machine program file on PC then sneaker-netting it to the machine. The DPV file format is really easy to understand, plus the guys at Sparkfun already did some of the work for the smaller machines which has only marginal differences to the "big one".@Ribster:I was facing the choice of Charmhigh vs. Yingxing vs. QiHe. In the end I took Yingxing out of the list because I could find virtually no information outside of their sparse sales documentation, and the only independently reported experiences were *meh*. Kimi then made me a great offer (ok, I bought a lot of feeders and a Conveyor Reflow oven at the same time) and they were super flexible regarding the "shipping" options (I used a railroad carrier, which ended up being only about ~35% of the cost of TNT, and still over two times faster than actually ocean shipping). As for Aliexpress vs. other ways of buying; YMMV, but I think they are generally trustworthy. Did pay via bank transfert and would again.Regarding the "benchtop" part, yes. Still you need a really sturdy bench. The machine weights about 190kg I think, plus feeders, so the bench should be able to support over 300kg on about 1.5m².Btw. their CL feeders come with a unique barcode from the factory, so you don't have to slap your own QR code on there. I went for 50 8mm feeders then 30 of each 12mm and 16mm and a few 24mm ones. I didn't buy the tube feeder.I have my standard parts (common resistor and caps as well as 0805 R/G/B leds, two uCs, common diodes) as well as some common connectors always loaded on the machine. Then this leaves me about half of the slots free for project specific reels. For small batches I tend to populate only what's available on the machine already and do the remainder by hand (by experience that's more cost effective surprisingly long).Regarding the software part, I have plans for something like what you have in mind too, just a terrible lack of time. Maybe we could join forces on that if we have enough common goals.