Think & Tinker, Ltd.
P.O. Box 1606, Palmer Lake, CO 80133
Tel: (719) 488-9640, Fax: (866) 453-8473
Sales: Sales@ThinkTink.com, Support: Support@ThinkTink.com
Think
&
Tinker
Ltd.





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Setting up a PCB Shop

In many regards, a printed circuit prototyping shop is very similar to a photographic darkroom in both form and function. In both cases, photosensitive materials are to be processed, and most of the processing steps use aqueous (water based) chemicals of varying degrees of toxicity. Fortunately, the increasing environmental awareness of the past decade has resulted in families of plating and etching chemistries that are much safer and easier to use than ever before. Nonetheless, the primary considerations when setting up your PCB Fab Lab for making PCBs are:

Shop Safety

Convenience

For some reason, when setting up a shop for the first time, there seems to be an irresistible compulsion to spread out as far as possible, to occupy as much floor space as can be captured without overt aggression.Well, don't do it. A well laid out, uncluttered, compact laboratory is far more efficient and less likely to become a dumping ground for all of that scrap that you just can't bear to part with.

Facilities

What you will need in terms of floor space, utilities, ventilation, and chemical handling/disposal, will depend a great deal on the quantity and type of PCBs you want to make. With an unquenchable desire to stereotype people and pigeon-hole their complex needs into narrow, ill fitting categories, we have come up with the following user classifications.
  1. I only need to make a single PCB, but I need it right away. I don't intend to make any more (or many more) boards in the future.

    Making a high quality PCB can be quite simple, but it is never trivial. If you only need a single board, and do not have a desire to learn the processes and disciplines that will be required to make it yourself, I would advise you to find a board shop that will make it for you. The front end costs of using a quick turn board shop might seem high, but they will be an order of magnitude less (in time and money) than the cost of learning to do it yourself.

    Having said that, I might also mention that the art and practice of PCB prototyping is quite interesting. I have found that it can be very enjoyable if you are not subject to time constraints that demand that you master the art RIGHT NOW. It requires that you learn a set of related disciplines that find uses in many other fields of endeavor, so the rewards extend far beyond just making your own PCBs. Besides, you really will have etchings that you can invite your date up to see.

  2. I would like to have a shop where I can make a couple of simple (0.020" traces and spaces, 50 to 200 through-holes) PCBs per week. Through hole plating is not required.

    The lab set up that you will need depends on whether you have the ability to make (or access to) negative artwork from your PCB CAD data. The Green CirKit© process assumes that you will be using dry-film photopolymers (photoresist and soldermask), both of which are negative acting or "contrast reversing". This means that the areas of the photopolymer that are shadowed by your artwork are dissolved away during developing and areas that are exposed to UV light cure and remain behind. Since most Green CirKiteers do not have home photoplotters, and laser and ink-jet printers do an abominably poor job of reverse printing, positive artwork is most often used.

    The most reliable way to make a production quality PCB using positive artwork is to use what is referred to as a semi-additive process that relies on pattern plating both copper and tin/lead (solder). If negative artwork is available, you can skip the tin/lead bath and use a single panel plating step to build up the surface copper and coat the through-holes.

    The basic needs of your shop can be separated into two major categories. Stand alone equipment and facility improvements.

    Facility Improvements Description / Reason
    • Sink
    - stainless steel sink with a sideboard or a double sink with a drop in side board. Add a hand sprayer (hand wand) that will allow you to blow debris and board cleanser out of the through-holes during cleaning. The sink should be big enough to allow you to easily clean your largest board. The sideboard will provide a surface that is easy to keep VERY clean (which you should do religiously).
    • Work benches
    - at least 1 ea. 3' x 6' work benches 34" to 36" high. When you are making PCBs, you can never have too much horizontal surface to work on. Actually, this is true of life in general, so don't short change yourself here.
    • Ventilation
    - a wall or window mounted, low-noise exhaust fan with adjustable baffles to allow you to control the air flow is preferred, but you may be able to get by with opening the door and windows in your shop while you are operating. With acrylic monomers boiling off of the photoresist and soldermask, small amounts of aerosol sulfuric acid coming off of the plater and etcher, and micro-fine dust being kicked up by the board drill, it is very good idea to provide ventilation that exchanges the entire volume of air in your work shop 5 or 6 times an hour (minimum).
    • Flammable and corrosive chemical storage
    - flammable and corrosive materials must be stored away from each other. All flammables should be kept in an OSHA and UL (MH10234) approved storage locker. This is not just being picky. Proper storage of hazardous materials makes good sense for your personal safety, the security of your business, and the protection of the environment all of which are central tenants of the Green CirKit© discipline.
    • Emergency shower / eye wash
    - many of the baths used in PCB fabrication have the potential to cause severe damage to the eyes and skin. An emergency eye wash station will pay for itself the first time you have to use it. A Bradley Kleersight™ self contained emergency station (Grainger #2P331) is a good alternative to a plumbed-in fountain.
     
    Equipment Description / Reason
    • Drill press
    - for low volume through-hole and drilling holes larger than 1/4" dia.. Also good for sheet metal work when building enclosures. If you are buying one for the first time, choose a floor standing model with adjustable table and spindle positions. If you have the money, a Mill/Drill combination is a VERY handy tool to have in a shop. Check with Manhattan Supply, Enco, or Northwestern Supply. In any case, make sure that it is easy to adjust the speed to accommodate different drilling conditions.
    • Shop vacuum
    - vacuum cleaner that can be used to with CNC drill to remove drilling and routering debris. It will also be used to remove excess ink during holewall activation. Check out the W.W. Grainger's Dayton 6Z925, a rather cleverly designed unit that combines a shop vacuum cleaner with a portable electric blower.
    - for this level of activity, a pouch style laminator is recommended. Check out the Model PL-120ap. Photopolymers and backing materials are available from a number of vendors, but prices remain rather steep.
    • Etcher
    - choose a chemistry that is continuously replenishable, stable, and easy to control. You should use an immersion etcher and heat the etchant in a covered stainless steel pan on the oven. Do not use a microwave as they tend to make copper containing solutions boil over. You also do not want sulfuric acid fumes drifting around in the control electronics of your oven. Most consumables are readily available from a number of sources with prices ranging from reasonable to "you gotta be kidding me!".
    • Sn/Pb plater
    - actually part of the circuit imaging process. In the absence of negative artwork, pattern plating with tin/lead (solder) establishes a resist layer that offers superior protection against most commercially available etchants. Most consumables are readily available from a number of vendors, but finding sources of small to moderate volumes (1 to 5 gallons) remains a problem. Prices remain fairly high.
    • Developer
    - use a Pyrex dish with 1/2" of heated developing solution in the bottom. The developing bath is a 1.5% (wt.) solution of common soda ash (anhydrous sodium carbonate) or sodium carbonate monohydrate
    • Rinse tanks
    - a separate rinse tank should follow every process tank. If you adhere to this practice, rinse water can be added back into the process tanks to replace evaporative losses. This results in a near zero effluent system and insures that all valuable bath components are preserved. Do not add the rinse water from one process back into the tank of another! An 18" x 4" x 24" polyethylene tank with a corner fitted flush mounted bottom drain (US Plastics P/N 11202) is just about the perfect size to allow any board to be swished back and forth to clean out all of the through-holes.
    - the UV power spectrum of your source must match the requirements of the photopolymer you are exposing. The outputs of unfiltered high-pressure mercury vapor lights and low-pressure BLB fluorescent tubes (bug zapper lights) match the absorption/curing characteristics of most popular photoresist and soldermask. For circuit geometries finer than 0.007", a high intensity collimated source with integral vacuum frame should be used.
  3. I would like to have a shop where I can make 1 or 2 moderately complex (0.012" traces and spaces, 300 to 500 through-holes) PCBs per week. Through hole plating is required.

    The lab set up that you will need depends on whether you have the ability to make (or access to) negative artwork from your PCB CAD data. The Green CirKit© process assumes that you will be using dry-film photopolymers (photoresist and soldermask), both of which are negative acting or "contrast reversing". This means that the areas of the photopolymer that are shadowed by your artwork are dissolved away during developing and areas that are exposed to UV light cure and remain behind. Since most Green CirKiteers do not have home photoplotters, and laser and ink-jet printers do an abominably poor job of reverse printing, positive artwork is most often used.

    The most reliable way to make a production quality PCB using positive artwork is to use what is referred to as a semi-additive process that relies on pattern plating both copper and tin/lead (solder). If negative artwork is available, you can skip the tin/lead bath and use a single panel plating step to build up the surface copper and coat the through-holes.

    The basic needs of your shop can be separated into two major categories. Stand alone equipment and facility improvements.

    Facility Improvements Description / Reason
    • Sink
    - stainless steel sink with a sideboard or a double sink with a drop in side board. Add a hand sprayer (hand wand) that will allow you to blow debris and board cleanser out of the through-holes during cleaning. The sink should be big enough to allow you to easily clean your largest board. The sideboard will provide a surface that is easy to keep VERY clean (which you should do religiously).
    • Work benches
    - at least 1 ea. 3' x 6' work benches 34" to 36" high. When you are making PCBs, you can never have too much horizontal surface to work on. Actually, this is true of life in general, so don't short change yourself here.
    • Ventilation
    - a wall or window mounted, low-noise exhaust fan with adjustable baffles to allow you to control the air flow is preferred, but you may be able to get by with opening the door and windows in your shop while you are operating. With acrylic monomers boiling off of the photoresist and soldermask, small amounts of aerosol sulfuric acid coming off of the plater and etcher, and micro-fine dust being kicked up by the board drill, it is very good idea to provide ventilation that exchanges the entire volume of air in your work shop 5 or 6 times an hour (minimum).
    • UV proof illumination
    - allows photopolymers to be stored in the open and insures that laminated boards are not "fogged" during artwork alignment and imaging. The easiest way to remove virtually 100% of the UV flux from your work area is through the use of thin film coated filter sleeves and sheets on fluorescent lights and windows.
    • Flammable and corrosive chemical storage
    - flammable and corrosive materials must be stored away from each other. All flammables should be kept in an OSHA and UL (MH10234) approved storage locker. This is not just being picky. Proper storage of hazardous materials makes good sense for your personal safety, the security of your business, and the protection of the environment all of which are central tenants of the Green CirKit© discipline.
    • Emergency shower / eye wash
    - many of the baths used in PCB fabrication have the potential to cause severe damage to the eyes and skin. An emergency eye wash station will pay for itself the first time you have to use it. A Bradley Kleersight™ self contained emergency station (Grainger #2P331) is a good alternative to a plumbed-in fountain.
     
    Equipment Description / Reason
    • CNC Drill
    - single spindle machine with a minimum 12" X 18" format, 0.001" addressable resolution, 0.001" absolute accuracy, 0.0005" repeatability, spring loaded or air activated pressure foot, vacuum debris removal, min. 35,000 rpm spindle, XY contour routing capability and 100% Gerber data-file compatibility is absolutely essential for the low to medium volume fabrication of production quality printed circuits. Automatic tool change and panel routering capabilities are nice but can be added later as your needs dictate. Solid carbide drill bits, routers and end-mills with depth setting rings are available from a large number of vendors. Pricing is very competitive.
    • Shop vacuum
    - vacuum cleaner that can be used to with CNC drill to remove drilling and routering debris. It will also be used to remove excess ink during holewall activation. Check out the W.W. Grainger's Dayton 6Z925, a rather cleverly designed unit that combines a shop vacuum cleaner with a portable electric blower.
    • Lab oven
    - large enough to hold the largest board that you intend to do. Needed to cure the conductive ink as well as drying boards prior to ink application and dry film lamination. Do not buy an oven bigger than you need.
    - for this level of activity, a production grade laminator is recommended but a pouch style laminator can be used. Depending on the panel size that you will standardize on, check out the Model 2200 or Model 3200. Their safety clutches make the process of changing films with minimum waste very easy. If you will be using both photoresist and soldermask on your boards, this capability will keep you from needing a second laminator until your shop volume demands it. If you opt for a pouch style unit, the PL-120ap will meet your needs. Photopolymers and backing materials are available from a number of vendors, but prices remain rather steep.
    • Etcher
    - choose a chemistry that is continuously replenishable, stable, and easy to control. In a production environment, a spray etcher is a necessity. For lower levels of production (1 to 10 boards per week), and less demanding circuit geometries (min. 0.007" traces and spaces) you can use an immersion bath or a bubble agitated system. Most consumables are readily available from a number of sources with prices ranging from reasonable to "you gotta be kidding me!".
    • Cu plater
    - possibly the easiest component of your PCB lab to set up, use, and maintain. Most aspects of acid copper electroplating are well understood. There is a well developed infrastructure of vendors to support every facet. Most consumables are readily available from a number of vendors, but finding sources of small to moderate volumes (1 to 5 gallons) remains a problem.
    • Sn/Pb plater
    - actually part of the circuit imaging process. In the absence of negative artwork, pattern plating with tin/lead (solder) establishes a resist layer that offers superior protection against most commercially available etchants. Most consumables are readily available from a number of vendors, but finding sources of small to moderate volumes (1 to 5 gallons) remains a problem. Prices remain fairly high.
    • Developer
    - can be as simple as a Pyrex dish with 1/2" of heated developing solution in the bottom. Geometries finer than 0.012" traces and spaces require the use of bubble agitation. The developing bath is a 1.5% (wt.) solution of common soda ash (anhydrous sodium carbonate) or sodium carbonate monohydrate
    • Rinse tanks
    - a separate rinse tank should follow every process tank. If you adhere to this practice, rinse water can be added back into the process tanks to replace evaporative losses. This results in a near zero effluent system and insures that all valuable bath components are preserved. Do not add the rinse water from one process back into the tank of another! An 18" x 4" x 24" polyethylene tank with a corner fitted flush mounted bottom drain (US Plastics P/N 11202) is just about the perfect size to allow any board to be swished back and forth to clean out all of the through-holes.
    - the UV power spectrum of your source must match the requirements of the photopolymer you are exposing. The outputs of unfiltered high-pressure mercury vapor lights and low-pressure BLB fluorescent tubes (bug zapper lights) match the absorption/curing characteristics of most popular photoresist and soldermask. For circuit geometries finer than 0.007", a high intensity collimated source with integral vacuum frame should be used.
  4. I would like to set up a complete PCB lab capable of making 1 to 20 production quality boards (double sided and/or multilayer) at a time.

    The lab set up that you will need depends on whether you have the ability to make (or access to) negative artwork from your PCB CAD data. The Green CirKit© process assumes that you will be using dry-film photopolymers (photoresist and soldermask), both of which are negative acting or "contrast reversing". This means that the areas of the photopolymer that are shadowed by your artwork are dissolved away during developing and areas that are exposed to UV light cure and remain behind. Since most Green CirKiteers do not have home photoplotters, and laser and ink-jet printers do an abominably poor job of reverse printing, positive artwork is most often used.

    The most reliable way to make a production quality PCB using positive artwork is to use what is referred to as a semi-additive process that relies on pattern plating both copper and tin/lead (solder). If negative artwork is available, you can skip the tin/lead bath and use a single panel plating step to build up the surface copper and coat the through-holes.

    The basic needs of your shop can be separated into two major categories. Stand alone equipment and facility improvements.

    Facility Improvements Description / Reason
    • Sink
    - stainless steel sink with a sideboard or a double sink with a drop in side board. Add a hand sprayer (hand wand) that will allow you to blow debris and board cleanser out of the through-holes during cleaning. The sink should be big enough to allow you to easily clean your largest board. The sideboard will provide a surface that is easy to keep VERY clean (which you should do religiously).
    • Work benches
    - at least 1 ea. 3' x 6' work benches 34" to 36" high. When you are making PCBs, you can never have too much horizontal surface to work on. Actually, this is true of life in general, so don't short change yourself here.
    • Ventilation
    - a wall or window mounted, low-noise exhaust fan with adjustable baffles to allow you to control the air flow is preferred, but you may be able to get by with opening the door and windows in your shop while you are operating. With acrylic monomers boiling off of the photoresist and soldermask, small amounts of aerosol sulfuric acid coming off of the plater and etcher, and micro-fine dust being kicked up by the board drill, it is very good idea to provide ventilation that exchanges the entire volume of air in your work shop 5 or 6 times an hour (minimum).
    • UV proof illumination
    - allows photopolymers to be stored in the open and insures that laminated boards are not "fogged" during artwork alignment and imaging. The easiest way to remove virtually 100% of the UV flux from your work area is through the use of thin film coated filter sleeves and sheets on fluorescent lights and windows.
    • Flammable and corrosive chemical storage
    - flammable and corrosive materials must be stored away from each other. All flammables should be kept in an OSHA and UL (MH10234) approved storage locker. This is not just being picky. Proper storage of hazardous materials makes good sense for your personal safety, the security of your business, and the protection of the environment all of which are central tenants of the Green CirKit© discipline.
    • Emergency shower / eye wash
    - many of the baths used in PCB fabrication have the potential to cause severe damage to the eyes and skin. An emergency eye wash station will pay for itself the first time you have to use it. A Bradley Kleersight™ self contained emergency station (Grainger #2P331) is a good alternative to a plumbed-in fountain.
     
    Equipment Description / Reason
    • CNC Drill
    - single spindle machine with a minimum 12" X 18" format, 0.001" addressable resolution, 0.001" absolute accuracy, 0.0005" repeatability, spring loaded or air activated pressure foot, vacuum debris removal, min. 35,000 rpm spindle, XY contour routing capability and 100% Gerber data-file compatibility is absolutely essential for the low to medium volume fabrication of production quality printed circuits. Automatic tool change and panel routering capabilities are nice but can be added later as your needs dictate. Solid carbide drill bits, routers and end-mills with depth setting rings are available from a large number of vendors. Pricing is very competitive.
    • Shop vacuum
    - vacuum cleaner that can be used to with CNC drill to remove drilling and routering debris. It will also be used to remove excess ink during holewall activation. Check out the W.W. Grainger's Dayton 6Z925, a rather cleverly designed unit that combines a shop vacuum cleaner with a portable electric blower.
    • Air compressor
    - not strictly necessary, but a compressor is very handy for cleaning out spindles and blowing ink out of very small diameter through-holes. We find that a Thomas T-20HP (Grainger's No.5Z406) is a good compromise between quiet operation and high-pressure throughput.
    • Lab oven
    - large enough to hold the largest board that you intend to do. Needed to cure the conductive ink as well as drying boards prior to ink application and dry film lamination. Do not buy an oven bigger than you need.
    • Drill press
    - for drilling holes larger than 1/4" dia. and for sheet metal work when building enclosures. If you are buying one for the first time, choose a floor standing model with adjustable table and spindle positions. If you have the money, a Mill/Drill combination is a VERY handy tool to have in a shop. Check with Manhattan Supply, Enco, or Northwestern Supply. In any case, make sure that it is easy to adjust the speed to accommodate different drilling conditions.
    - for this level of activity, a production grade laminator is recommended but a pouch style laminator can be used. Depending on the panel size that you will standardize on, check out the Model 2200 or Model 3200. Their safety clutches make the process of changing films with minimum waste very easy. If you will be using both photoresist and soldermask on your boards, this capability will keep you from needing a second laminator until your shop volume demands it. If you opt for a pouch style unit, the PL-120ap will meet your needs. Photopolymers and backing materials are available from a number of vendors, but prices remain rather steep.
    • Etcher
    - choose a chemistry that is continuously replenishable, stable, and easy to control. In a production environment, a spray etcher is a necessity. For lower levels of production (1 to 10 boards per week), and less demanding circuit geometries (min. 0.007" traces and spaces) you can use an immersion bath or a bubble agitated system. Most consumables are readily available from a number of sources with prices ranging from reasonable to "you gotta be kidding me!".
    • Cu plater
    - possibly the easiest component of your PCB lab to set up, use, and maintain. Most aspects of acid copper electroplating are well understood. There is a well developed infrastructure of vendors to support every facet. Most consumables are readily available from a number of vendors, but finding sources of small to moderate volumes (1 to 5 gallons) remains a problem.
    • Sn/Pb plater
    - actually part of the circuit imaging process. In the absence of negative artwork, pattern plating with tin/lead (solder) establishes a resist layer that offers superior protection against most commercially available etchants. Most consumables are readily available from a number of vendors, but finding sources of small to moderate volumes (1 to 5 gallons) remains a problem. Prices remain fairly high.
    • Developer
    - can be as simple as a Pyrex dish with 1/2" of heated developing solution in the bottom. Geometries finer than 0.012" traces and spaces require the use of bubble agitation. The developing bath is a 1.5% (wt.) solution of common soda ash (anhydrous sodium carbonate) or sodium carbonate monohydrate
    • Rinse tanks
    - a separate rinse tank should follow every process tank. If you adhere to this practice, rinse water can be added back into the process tanks to replace evaporative losses. This results in a near zero effluent system and insures that all valuable bath components are preserved. Do not add the rinse water from one process back into the tank of another! An 18" x 4" x 24" polyethylene tank with a corner fitted flush mounted bottom drain (US Plastics P/N 11202) is just about the perfect size to allow any board to be swished back and forth to clean out all of the through-holes.
    - the UV power spectrum of your source must match the requirements of the photopolymer you are exposing. The outputs of unfiltered high-pressure mercury vapor lights and low-pressure BLB fluorescent tubes (bug zapper lights) match the absorption/curing characteristics of most popular photoresist and soldermask. For circuit geometries finer than 0.007", a high intensity collimated source with integral vacuum frame should be used.
    • Vacuum frame
    - only necessary if your UV source is not already equipped with one. Removes all of the air from between your artwork and the coversheet of the dry-film photopolymer to insure intimate contact during exposure. Essential if circuit geometries below 0.010" are encountered.
    • Multilayer lamination press
    - only necessary if you plan to make multilayer boards. Commercial units are VERY expensive and usually require 220 VAC single phase or 208 VAC three phase power. Effective home presses can be made for under $300.


Established 1990

On the web since 1994

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Sales: 1-(719) 488-9640    Tech Support: 1-(719) 488-9640    Fax: 1-(866) 453-8473
Copyright © 1994 - 2014 Think & Tinker, Ltd. Updated 2/13/2014 8:36:58 AM