Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Solder paste layout

Ken

#6552

Solder paste layout | 10 May, 2001

Good morning, We are presently using a couple surface mount parts on our circuit boards. We send the boards out of house to have the SMD parts placed. I have been told that the apertures for the stencil for each SMD are not to be 1:1 with pad. their is an industry standard that is smaller, which allows for the solder past to spread out when the part is placed. I would like to find this standard. Any advise or information would be useful. Thank you

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#6553

Solder paste layout | 10 May, 2001

I am unaware of any industry standard for specifying apertures for SM stencils. I am aware of IPC-7525, Stencil Design Guidelines. You can obtain it from IPC [http://www.ipc.org].

Further, it seems like there is an article on stencil design every other month in one trade journal or another. Consider checking the article achives for such magazines [eg, SMT, Circuit Assembly, etc]. One example is "Step 4 - Printing", R Prasad, SMT Magazine, April 2001, p. 88.

Industry standard or no industry standard, it seems to be a risky proposition to issue production work prior to fully considering, evaluating, and resolving the differences between the requirements for assembling the product and capabilities of the production processes, including those of your partner, that you plan to use in assembling your product.

Much has been written about design for manufacture [DFM]. Earl Moon published several articles on the topic in the SMTnet Newsletter. Other DFM references are:

Manufacturing Processes, 8th ed., B.H. Amstead, P.F. Ostwald, Myron L. Begeman, John Wiley & Sons, 1987, ISBN 0-471-84236-2

Design for Manufacturability: A Systems Approach to Concurrent Engineering and Ergonomics, M. Helander and M. Nagamachi, eds., Taylor & Francis, 1992, ISBN 0-7484-0009-5

Anzivino, Rich, The DFM Design Philosophy, Printed Circuit Design, December 1994, pp. 14-18.

Webb, Scott E., Implementing DFM, Printed Circuit Design, December 1994, pp. 10-13.

Potechin, Jamey, Integrating DFM, Printed Circuit Design, November 1993, pp. 22-26.

Blankenhorn, James C., A Rose by Any Other Name Or, What is Design for Manufacturability?, Printed Circuit Design, August 1993, pp. 15-17.

LeBrun, Jim, Design for Manufacturing, EDN Products Edition, November 17, 1995.

Mraz, Stephen J., Curing Design Blues, Machine Design, November 7, 1994, pp. 69-72.

Pallanck, R., Sandberg, E., et. al, How to Make Concurrent Engineering Work, Part 9: Managing the Work Flow, Machine Design.

Baumgartner, Dan, Quick-Turn Design and DFM, Printed Circuit Fabrication, Vol. 19, No. 3, March 1996.

Jodoin, Claude J., Good Design Means Good Manufacturing, Printed Circuit Design, August 1994, pp. 34-35.

Jodoin, Claude J., Designer's Viewpoint, Printed Circuit Design, July 1994, pp. 36-37.

Jodoin, Claude J., Designer's Viewpoint, Printed Circuit Design, March 1995, pp. 58-59.

Jodoin, Claude J., Designer's Viewpoint, Printed Circuit Design, November 1993, pp. 40-41.

Glover, Rita, PCB Leapfrogs Into System-Level Design, Electronic Design, April 1st, 1996, pp. 83-84.

Dolberg, Schmil, Tomorrow's Tools for PCB Preproduction, Printed Circuit Fabrication, May 1995.

Silva, Joseph, High-Performance Design, Printed Circuit Design, March 1995.

Gentry, Teresa, Excellence in PCB Design, Printed Circuit Design, Vol. 10, No. 11, November 1993, pp. 16-21.

Kovarsky, Moshik, Tools of the Trade, Printed Circuit Fabrication, Vol. 19, No. 3, March 1996.

Neural-Net Autorouter Analyzes Layouts, Adapts Routing Costs, Personal Engineering, May 1995, pp. 21-22.

Lindgren, Russ, Design-Rule Checks Help Users Create Complex Layouts, Personal Engineering, May 1995, pp. 24-28.

Potechin, Jamey, The DRC Lie, Printed Circuit Design, August 1994, pp. 18-21.

Gomez, Dick, Design Reuse Accelerates Board Creation, Electronic Design, July 25, 1992, pp. 77-88.

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#6557

Solder paste layout | 11 May, 2001

Hi KP,

I�m wondering why you send those boards outhouse for the SMD part with a stencil. How do you know it fits their printer.

We give the stencil data 1:1 to the subcon so that they can order the stencil to their needs with reduction and thickness they can live with best. The price for us the same.

Nevertheless, the IPC is a good guide, you should have it to know what to take into account while designing a Board.

Wolfgang

.....Dave , what do you do outside your workplace ? I hope ( ...na, I know you don�t ... ) not only reading !

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#6561

Solder paste layout | 11 May, 2001

Wolfgang

Tomorrow [Saturday] Lucy and I are getting-up at 6AM, shaking-off the effects of Jimbo's from the night before, grabbing the Leicas and fowl [inclement] weather gear to search for migrating warblers in what is forcasted to be a near-freezing rain storm of substance. Talk about outside interests!!!

Don't worry about me, buddy.

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