Fast PCBA quick turn around times tips - Page 1
Forum section: electronics / general

author: nevic
author_rank: Newbie
timestamp: October 08, 2018, 12:38:44 pm
content: Hi,I'm hoping that people may be able to give me tips on how best to achieve fast turn around times for PCBA? Are their specific vendors that facilitate fast turn around? We like to order in batches between 100-200. It seem to take 6 weeks plus. We have tried pcbcart and pcbway.We currently let the assembly business source the components from the the BOM.We were considering purchasing all the components in and then sending them to the assembly manufacturer.Does anyone have any ideas or tips to facilitate fast turn around times?regards,

author: SMTech
author_rank: Frequent Contributor
timestamp: October 08, 2018, 01:41:40 pm
content: On those occasions where we have had to make use of an external contractor 5 weeks+ seems to be pretty much the norm with quite a few being longer than that. It probably depends a bit on where you are, it would seem in the UK for example that a lot of places are currently very busy, that pushes lead times out, especially for smaller batches. To be able to truly turn things around very quickly really requires the contractor to have a line that is not fully utilised, which isn't often a desirable situation.Kitting the parts yourself could help, provided you make sure you understand how they want their parts kitted, however even then we have seen lead times where the time doesn't even start to count down until that kit enters the building (presumably to avoid the "it's on the way honest guv" lies people might tell to get themselves higher up the queue). Bigger batches can help, or if the contractor offers it - call offs that let them plan well advance for your years/period of choice requirement. What can also help tho' is understanding why 6 weeks isn't good enough, can you adjust your processes to make that work?Equally it could just be a case of finding a contractor that's a good fit for you who can work to those timeframes. Here we would normally expect to be able to do 3 weeks without too much difficulty where we source everything. While a week or less is technically possible in the current climate its quite hard to do, the timeslot has to be there, the parts have to be in stock on the right continent in the right packaging and the distributor has to ship the part you ordered, something we are currently finding happens less reliably than it should in the case of RS and Farnell, particularly when you are buying quantities that mean cut tape or re-reels, if sods law can strike, it will. I don't think our ability to deliver in those lead times is all that unique, I would expect something similar to be possible in Aus, I would look local and look small, what you are looking for is probably a specialist or someone like us that mixes OEM and contract manufacture.As an example last month I build 10 each of several fairly massive boards for a company around the corner, they kitted everything because they kit for their volume contractor anyway, I was building those boards 2 days after they send the files over for a quote. When I found kitting errors they were there 20 mins later with the correct part, if that had been a Mouser only that could easily have been a 2/3 day spanner in the works (something very odd happens between the USA and the UK with DHL, parcels frequently seem to miss the plane in France on their tracking) and the jobs we had queuing up behind would have had to take priority, in that instance that would have added 2 weeks (because it would have been their fault).

author: ChristopherN
author_rank: Unknown
timestamp: October 08, 2018, 06:21:21 pm
content: I've just ordered 5 boards (fairly simple) from ALLPCB. They quoted 11-13 working days + DHL shipping (2-3 days) including PCB production, parts order and assembly.

author: rea5245
author_rank: Frequent Contributor
timestamp: October 08, 2018, 06:28:36 pm
content: Where are they ordering the parts from? I've had Chinese manufacturers order parts from the US and it takes a couple of weeks just for them to get the parts.Also, I'm not sure if they fabricate the PCBs while they're waiting for the parts to be delivered, or only after the parts arrive.- Bob

author: nevic
author_rank: Newbie
timestamp: October 08, 2018, 08:43:36 pm
content: Thank you for the replys!The last Batch of 100 of assembled PCB's we ordered from PCBWAY has just been 6 weeks from their received payment and no sign of dispatch.I'm not sure how they project managed individual parts and ordering of. I know the electronic engineers were a little frustrated as they had complied the BOM's with parts availability in mind and by the time PCBWAY got round to ordering we had 1 or 2 components out of stock. When questioned they seemed to point at problems at getting parts through customs about lead times.We just wondered if we somehow project managed the process more if they would be more time efficient. When using PCBWAY for PCB's prototypes they have been brilliant often receiving PCB's in less than a week to rural Australia.It is frustrating because we can do small run prototypes fully hand assembled ourselves in less than 10 days from when we order PCB's and parts.

author: mrpackethead
author_rank: Super Contributor
timestamp: October 08, 2018, 09:48:48 pm
content: Your fustrations are why i brought everything in house so we can do our own manufacturing.Last week i shipped 200 units of a product, just 6 days after the PCBs arrived. When you are a small fish in a big sea, finding your own small aquarium to live in might be an option.

author: nevic
author_rank: Newbie
timestamp: October 08, 2018, 09:55:35 pm
content: Doing our own assembly I can see would have its advantages. My feeling is at this stage we could be slightly to small volume to justify at the moment. However I'm quite interested to know the best way to do this to keep in consideration for the future.

author: mrpackethead
author_rank: Super Contributor
timestamp: October 08, 2018, 10:00:22 pm
content: How many different parts are on your BOM(s)do your different products share parts?What kidn of volumes are you producting?

author: nevic
author_rank: Newbie
timestamp: October 08, 2018, 10:38:46 pm
content: Hi,Currently we have 2 production boards. With approx. 100 unique components although we have room to standardize more.Yes we share parts. I would have to audit / discuss with engineers to be precise.We are prototyping a 3 additional boards with production to start in less than a month. However these are quite small and would add less than 50 unique components.So to summarize at most we would use 150 unique components.thanks

author: mrpackethead
author_rank: Super Contributor
timestamp: October 09, 2018, 01:57:51 am
content: Quote from: nevic on October 08, 2018, 10:38:46 pmtheres often lots of times you can make some substituions.. First start by looking at critical value parts. There are sometimes part values you just can't swap. then look at other parts. For example, you might have a pull up/down resistor somewhere. You might have put in a 10k part, but in fact, anythign betgween 2k and 50k might work just fine. Do you have anything that value in your critical list? I'm often doing DC/DC converters, and will have a pair of resitors in a divider. What is important is the ratio begween them. Again you might be able to substitute parts and reduce your bom by one part. You probaby have 100nF caps all over yoru board for bypass. But would a 68nF ( that you are using as part of a filter for example ) be ok? Sometime you might even put two parts in parrallel or series... ( do this carefully )Set up a strict library that all design must pull their parts from. if you really need a new part then make somone justify why. ( sometims you have to. but do it for a reason, not just because )

author: ar__systems
author_rank: Frequent Contributor
timestamp: October 09, 2018, 03:43:33 am
content: Quote from: ChristopherN on October 08, 2018, 06:21:21 pmThey all will quote you two weeks. The reality will be different.The only way is to pay $1000 for your assembly and order from North America. Then there is a chance you'll get your board assembled fast.

author: mrpackethead
author_rank: Super Contributor
timestamp: October 09, 2018, 04:18:20 am
content: Quote from: ar__systems on October 09, 2018, 03:43:33 amThe North Americans are not the only people who can assemble fast. In fact, theres Australia, New Zealand, India, China, Malaysia... Lots of places in Europe.Curious, have you had first hand expereince of every fab in China?

author: nevic
author_rank: Newbie
timestamp: October 09, 2018, 08:58:52 am
content: So it seems the only certain option is to buy a PnP ? that's frustrating. Would it be a viable business to offer to do fast turn around prototypes for people? It would be expensive but for low volume prototypes the cost per board wouldn't be as important.thanks

author: mrpackethead
author_rank: Super Contributor
timestamp: October 09, 2018, 09:22:06 am
content: The 'Killer' for automatic placement is setup time.- It takes time to load parts onto reels, place them on the machine, and make sure that the machines know where the parts are.- It takes time to configure your pnp machine knows how to handle a part. Can it image it, does it know the right dimensions. how is it in the reel.If i had to load 100 parts from sctrach on my machines, and configure the pnp, it could easily be a 6 task.. Maybe more. For doing 'random' contract work, this is a cost that needs to be covered each time. And its time the machines wont' be running..In our fab, our parts never come off the machines, they are loaded all the time. The only time a feeder comes off, is if its got a problem or its empty. our back end systems can generate the program files really quickly and i can swap between jobs in only a few minutes.It takes a LOT of time and effort to get to this point though. If you are only doing a couple of boards, you mgiht be better off doing manual hand assembly in house. it can often be faster than automatic work.

author: nevic
author_rank: Newbie
timestamp: October 09, 2018, 09:51:17 am
content: thanks,We already do manual assembly of prototype boards. This is for quick turnaround. But I understand your point about doing work for other people, the setup times will kill it.I'm really looking for solutions for our batches of 100 boards. If we can do a hand assembly of 5 boards in less than 10 days from ordering PCB's and components, it must be possible for a business to offer this turn around. However I guess they have the same issue with setup overheads etc.It would be a lot of work to run our own PnP. Really the only advantage would be turn around times. Cost per board would go up doing it ourselves.cheers

author: SMTech
author_rank: Frequent Contributor
timestamp: October 09, 2018, 10:49:00 am
content: Loading 100 brand new part numbers into the system would take me a couple of hours assuming only a handful were exotic new shapes I hadn't seen before.Creating a new "Recipe" for a brand new customer using those new parts and their pick and place file, maybe as much as another couple of hours while I learn their CAD output quirks, rotations etc.Creating a brand new recipe for a customer whose parts I already have on the system and have used before - 20 minutes.Loading 100 parts onto the feeders to build a job if they are all supplied as reels <2 hours on my own, scale that up significantly for parts supplied on cut tape where I need to at least add cover tape extensions potentially splice together multiple short strips, and mutter abuse at you under my breath. Most subcontractors have significantly more feeders that they need at any one time meaning a kitting team can be loading one job onto a trolley while another job is running. We don't have that privilege because we are a small company and because feeders are a very significant investment meaning that they effectively tie you to a machine manufacturer (they are usually compatible across generations).Factory time with overheads isn't cheap regardless of how little you need to pay your workers, some of the pricing offered by Chinese services has to be loss leading so I wouldn't want to rely on them too heavily; the salaries in Chinas tech cities are lower than here, but not THAT low.

author: ar__systems
author_rank: Frequent Contributor
timestamp: October 09, 2018, 12:35:18 pm
content: Quote from: mrpackethead on October 09, 2018, 04:18:20 amThe answer is obvious. Well I said North America since I'm here. Sure there are well organized places in many western countries. And in Asia too, just not very likely the first random PCBA shop..

author: mrpackethead
author_rank: Super Contributor
timestamp: October 10, 2018, 02:15:25 am
content: Quote from: ar__systems on October 09, 2018, 12:35:18 pmWhere-ever it is, it aint going to be cheap.