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SMT prototyping service questions
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SMT prototyping service questions

by dave915 on Wed Jun 10, 2015 10:46 pm

Hey everyone,

I have been an adafruit customer for quite sometime but never really looked at the forums until recently. About a year ago I was able to purchase a second hand Manual pick and place system (with Vision) and a reflow oven to make a couple of prototypes for one of my projects. The used equipment was sold to me for 1 dollar by a family friend that was going to throw them away as trash. They were very badly neglected and after a couple of weeks of machining new parts they were both in good working order. Since then I have been helping several of my friends and their friends by building their SMT prototypes for their electronics classes and have only been charging them meal vouchers (they are broke and so am I). For the last 12 years I have worked as an electrical engineering technician assembling prototypes by hand, and with a automatic pick and place machine. I feel very confident of my ability to place a perfectly working board in a less than desirable atmosphere. I plan on expanding by business to accept more customers since I have a lot of down time available to me. But my question is what should I charge? what would you feel comfortable paying? I have been only accepting completely kitted kits, with the pcb's and parts while I have been providing the stencil. should I charge by the component? or a flat hour rate? or a Minimum rate? A month ago I was able to assemble a 225 component board in 4 hours and 30 mins. If anyone can provide any insight it would be greatly appreciated. I am currently working on a website and getting a business license to operate in the state.

dave915
 
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Re: SMT prototyping service questions

by bcoggs on Thu Jun 18, 2015 8:04 am

I would start with looking at electronics assembly technicians salaries in your part of the world. Say that comes to USD$X/hour.. As a buyer of direct freelance work I would expect to pay 1.5 to 2 * X per hour. If you were a big, established CM, I would probably pay 3..4x per hour. I would then time each labor step and quote on a per-job price which takes into account SMT BOM Count and number of placements.

I would personally say there is a potentially bigger need for freelance through-hole soldering and manufacturing test work than just SMT placement..

bcoggs
 
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Re: SMT prototyping service questions

by alphatronique on Thu Jun 18, 2015 10:22 pm

HI

that highly depend of your yield ,if 10% of the board work flawless it not same price as if 100% work ;-)
usually customer prefer paid more but have perfect board
one you confident that you able to make good working board ,you ma find local competitor and send a test board to it for qoute
then find a price that match were you what to be Vs the competition

if you what you may play whit my own online qoute tool ,usually i was not cheap ,but yield was excellent ,since i past > 20 year doing design
so i may catch error before delivery and was quite over qualified for SM assembly http://www.alphatronique.com/instant-quote/

not what to go to deep into formula i use ,but i take into account number of different part and time need for sort it etc etc and total number of part to place
once you knot how mutch it cost to you to handel a specific part number and how many part per hour you place you may calculate cost of a board to assemble ;-)

but a bit of cation toaster type oven ,not follow the MFG thermal profile of solder ,so personally i not think it good for any production

have fun ..

alphatronique
 
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Re: SMT prototyping service questions

by bcoggs on Sun Jun 21, 2015 8:25 am

There is another price quotation tool here: http://www.smallbatchassembly.com It reflects labor rates w/the overhead of a small business in the USA. Disclaimer: I own the business.

bcoggs
 
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Re: SMT prototyping service questions

by dave915 on Tue Jun 23, 2015 10:36 pm

Charging per hour and not component was what I currently doing, and your assessment of 1.5 -2 x the current tech salary rate in my area is what I am currently charging. I do have the ability to solder through hole components and have done many hybrids in the past as well as all through hole. I tend to relax when I am hand soldering a prototype with bus wire and a lot of IC sockets. I am trying to capture the niche market of smt prototyping since my set up rate will be much lower for a manual pick and place than an automatic with the only drawback being a longer delivery time. For a company this is detrimental but for an individual without the thousands of dollars of capital to spare an easy trade off. The reflow oven that I am using is not a toaster over but an essemtec prototyping conveyor oven from the 00's refurbished by me. I borrowed a slimkic from work to calibrate it and it has been working for quite a while now. It’s funny that you mention "manufacturing test work" as I work on automated test equipment at work which pays my bills during the day. My time structure will be something similar to 0603-cap-res X 1.5 seconds per placement x tech salary + 20-50 dollar setup = Price paid + shipping. As for my failure percentage I believe I have only repaired one board that I have built and that was a couple of years ago, I have my way of organizing my components and boards in order to eliminate my errors plus my eyesight is very good so I can read the values of components with identifier symbols for this reason I would only request PCB's without any leadless component that require xray inspection.

dave915
 
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Re: SMT prototyping service questions

by alphatronique on Fri Jun 26, 2015 10:53 am

HI

not forgot that cleaning the board was time consuming operation ( solvent clean + 2 rinse + drying up)
20-50$ for setup was low ,most of time part come mixed or badly identified ,equivalent part number ,so take time to sort it out 2 -3h was not un-usual
1.5 second was bit low for manual placement 2-3 second was bit better for have room for uncommon part or find REF-DEF

a good rule of thumb may something like 15-10 cent per SMD part + 0.3cent per trough hole pin + actual setup time

never forget that prototype and small volume was always more challenging that do full run ,it you that debug the assembly documentation ;-)
and also it you that deal whit PCB oupss ( bad thermal release on pad , wrong footprint etc etc so it add to time need to make board )

also X-ray requirement was quite a myth if you have good reflow and you control the process correctly it no pose a problem
it normally used only for debug process issue not for test every part ,even if smt shop like to tell that it test all part ;-)

have fun

alphatronique
 
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Re: SMT prototyping service questions

by dave915 on Tue Oct 27, 2015 5:30 pm

So guys quick update, its been a couple of months and so far everything has been going splendidly. I am currently averaging 4 customers a month building 2-15 boards per week, I can do more but this is what I am handed. I have had a couple of through hole prototype perf boards that needed to be assembled as well as some heavy populated double sided boards. If everything goes well in the next couple of months then I will definitely consider investing in some more expensive manufacturing equipment. I am just making sure that my customer base is not just seasonal and consistent through out 6 months.

dave915
 
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Re: SMT prototyping service questions

by ioadafzx on Sat Nov 14, 2015 8:11 pm

Hello,

Will the .lbr file attached work with the, NSSM124T, RGB LED?
What file will work for this LED?
Do you sell circuit board for this LED?
Thank you.
brian.ruth3000@gmail.com
Attachments
adafruit-Adafruit-Eagle-Library-fd5ad06.zip
(358.44 KiB) Downloaded 55 times

ioadafzx
 
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Re: SMT prototyping service questions

by dmpyron on Sun Nov 29, 2015 10:38 pm

Here are the considerations you should make: What do you want your gross pay rate to be. This would be the pay that your employer gave you, before taxes and all that other ugly stuff that keeps us from buying Ferraris on what we're making.

Now, if you are working straight off as self-employed you will need to add an additional half the amount of Social Security and Medicare (nb. this applies to the US only) that you will also pay as an individual. This is referred to as the "self-employment tax". If you work for someone else they pay that number (actually they pay the same rate as you). The difference is that "they" get to write that number off. (I work for my own corporation and this comes about with a great deal of painful paperwork, beginning in about 4 weeks).

Now there a bunch of other things you need to add in. Health insurance, if you pay for that. Worker's comp. State payroll taxes, if applicable. Most larger corporations use 100% as an overhead rate for the first 40 hours in a week or 2000 hours in a year.

So, if you feel that $10/hr is the prevailing wage in your area then add in this overhead number. Anywhere for 14.2% to 100% depending on a whole lot of things.

As always, talk to a lawyer and an accountant. If you're serious about doing this as a full-up business the $200 or so will be money well spent.

dmpyron
 
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