The reason you cling to 8/8 and drilling is because you know I cannot achieve it with my laser printer, and as for the drilling, you also know that I do not have a nice drill setup, which I have admitted to both. But lets talk quality of board output. The challenge above is something that we both can do.... So lets see who makes the best looking board.
I don't have a very good drilling setup either, and my 70 year-old eyes aren't as good as they used to be. We need drilled boards, so that top/bottom registration can be checked.
Okay Leon, but let's keep it simple for top/bottom registration and drilling. Let's make a 15/16 X 15/16 board with (4) small pads, one in each corner, and a 10/10 pattern in the center.
For the last couple of weeks, I have been experimenting with several aspects of making PCBs. Through these experiments, I have learned two very important aspects of PCB processing, which are:
Effectively controlling the temperature of the developer and etchant
Creating a productive PCB processing environment
By effectively controlling the temperature of the developer, my process has become much more consistent, and by effectively controlling the temperature of the etchant, my etching process has become much more expeditious. Furthermore, as another added benefit of better temperature control of the developer, I can now use a much stronger developer solution, which makes the developing process much more expeditious. At this point in time, I am currently using 12 grams of sodium hydroxide to 1 liter of water, however, I am getting ready to mix up a new batch with a new ratio of 14 grams of sodium hydroxide to 1 liter of water. In the past, I was using approximately 8 grams of sodium hydroxide to 1 liter of water, so this is a very significant increase, and my developing time is much faster.
As for creating a productive PCB processing environment, I would highly suggest to get organized. I am now much more organized for processing PCBs, as compared to the past, which has also had an impact on consistency and making the process more enjoyable. There are still quite a few things that I want to improve upon, but it all takes time and money.
To help you in your endeavors of creating your own PCBs, I would highly recommend reading these two threads:
Referring to the previous post and pertaining to Philmore DATAK Premier Series positive acting presensitized PCBs, 14 grams of sodium hydroxide to 1 liter of water is way too strong for the developer solution. 12 grams was working good, but I am still seeking the perfect solution for using "ROOTO Crystals of Household Lye Drain Opener" in combination with the Philmore DATAK Premier Series positive acting presensitized PCBs.
At least I now know the ideal mixture is somewhere between 12 and 14 grams per liter of water. As you might have guessed, I will attempt 13 grams for the next batch.
Referring to the two previous posts, 13 grams of sodium hydroxide to 1 liter of water seems to be a good ratio for the developer, however for some odd reason, it is making me decrease my exposure time. At 12:1, the premium exposure time was 1:35, and at 13:1, I am currently at 1:20 and still need to decrease the exposure time.
Okay, after messing around with 13:1 for a developer mixture on quite a few samples, I am now going to revert back to the 12:1, because the 13:1 seemed just a little to strong.
I sincerely appreciate the words of encouragement, but I must truly admit that it is not always fun. The successes are great, but the failures are torture.
I've always found making PCBs at home to be quite straightforward. With the software, printers and materials available these days, it's easier than ever.
LOL. Perhaps for you, but if you search some of my threads, you will find that I have said many times, "I am not a hobbyist". I am not performing all of these experiments as a hobby, I am performing them so others may enjoy their hobby.
I am adding this link to this thread for future reference. The method described in this "instructable" supposedly produces nice through hole plating for PCBs.
Well it has been a little over two years since this thread has seen any action, but I came up with a new idea this morning, and I do believe it belongs in this thread.
Since this thread started years ago, I have received plenty of flack pertaining to my method of making PCBs. While admittedly, there has been some challenges and a learning curve along the way, I have slowly been perfecting my method, stategies, and tools. My goal has always been to produce highly accurate double-sided boards. The trouble is that when you want high accuracy, everything becomes more complicated and more difficult to achieve. To make highly accurate boards using my method, which is an exposure frame method, everything must be highly accurate, which includes the PCB board size, the frame size, and the size of the positive or negative image, and today, I will be discussing a new method of making a highly accurate frame.
To start this discussion, let's begin by examining the illustration below, which contains two figures. Figure 1. depicts a cut away view of the exposure frame and the order in which the various components are layered. Firgure 2. depicts a cut away view of the exposure frame, with the various components in place. Although not shown, the perimeter of the exposure frame, tightly surrounds all of the layered components. The inside dimension of the exposure frame should have a little slop, just to allow removal of the layered components. In the past, I attempted a slight press fit, but have since abandoned that method, and I now try to achieve an exposure frame inner dimension of PCB board + 0.001", on both the width and length.
I suppose it is needless to say that it can be an arduous task to get a nice fit with all the various layered components. Since beginning this journey, I would have to say this was the hardest part of the PCB making process. Quality of the traces or pours, is really not all that difficult, once you have the process down pat, but achieving accuracy with an exposure frame method is a pain. As previously mentioned, I am always trying to perfect this method or find an easier way to achieve the accuracy that I desire.
In an attempt to get to the point, the construction of the exposure frame has always been a real pain. Basically the difficulty of making the exposure frame pertains to the material used, accuracy, and the machining processes available. With these difficulties in mind, I have always been searching for an easier way to make an exposure frame. Well this morning, while pondering the problems and possible solutions, I came up with a new idea for making highly accurate exposure frames, quickly and inexpensively. The solution lies in a previous experiment of mine, while reconstructing my PCB saw, and during this experiment, I used JB Weld to cast a critical part. To read about this experiment and the making of a highly accurate PCB cutting saw, please visit this thread: http://forums.parallax.com/showthread.php/156588-Trying-Something-New-Today-My-Latest-Experiment-A-Linear-Slide-Carriage.
From this point forward, I will now be casting my exposure frames, instead of constructing them from various materials. Since there is an endless possibility of various exposure setups, I will not be discussing the finer details needed to accommodate the various exposure setups, I will only provide the basic idea for obtaining a highly accurate frame, or more precisely, I will be discussing my setup. Referring back to Figure 1., my Platform Glass rests within a recess of my exposure setup and the Frame outer dimension has the same outer dimension as the Platform Glass. Regardless of the size of the actual PCB material, this process should be able to work for all my future exposure frames.
The required materials and steps are as follows:
Materials Required
Small brush with very fine bristles
Petroleum Jelly
Sheet of glass
Fill material (I will be using FRP, approx. 1/16" thick or something similar)
An aluminum or wax blank, machined to the final PCB outer dimensions + 0.001", on both the width and length (Please note that this blank should be taller than the fill material above, and I will be using 1/4")
JB Weld
Laquer thinner
Steps Required
Using the brush, coat an area of the glass slightly larger than the fill material with the Petroleum Jelly.
Cut out the center of the fill material to a dimension slightly larger than the aluminum or wax blank.
Place the fill material on top of the Petroleum Jelly coated glass.
Using the brush, coat the entire metal or wax blank with the Petroleum Jelly.
Place the metal or wax blank within the center of the cut out of the fill material.
Mix JB Weld with laquer thinner for thinning purposes, according to manufacturers instructions.
Fill in the gap between the metal or wax blank and the fill material, with the thinned JB Weld, allowing some overlap onto the fill material.
Allow the cast to fully cure.
Remove metal or wax blank from the cast.
** Please refer to the illustration below
EDIT: As mentioned, I am always looking for a better and easier method. With this in mind, I am now suggesting the creation of a blank made from 1/4" X 1/4" balsa wood, having an inner dimensions that are 0.001" larger than the PCB. I have worked with this balsa in the past and it is pretty easy to make an accurate frame with a disc sander and a hot melt gun. I believe this would be a lot cheaper material wise and it should also be a lot less time consuming. The main difference would be that this blank would not be coated with petroleum jelly and it would not be removed after casting, and in reality, it would become an actual part of the exposure frame, being bonded to the fill material with JB Weld.
To make construction easier, I may eliminate the 0.001" clearance, and just wrap and glue the balsa around the precut PCB material.
As a side note, it should be a breeze to obtain the necessary balsa, considering the largest balsa wood factory in the world is headquartered in the city where I reside
Anyhow, here is a new drawing for this concept.
WAIT!!!
I have another idea..... Simply spot glue the frame to the fill material... Easy, peasy, Japanesey
EDIT: On second thought, the spot glue method is not a good one, because it will allow stray light to pass
In reference to my previous post, I now have another idea...
In the previous post, I indicated that I would most likely be using FRP as my filler material, which I assume would work just fine, and it would also be pretty sturdy, to allow reuse and the making of multiple PCBs. However, everything I have done to this point, has been one of a kind PCBs and I imagine that trend will continue, although I do like the idea of only making an exposure frame once. Anyhow, for the quick, down, and dirty exposure frame, which would be suitable for one of a kind usage, I now have a different stategy, for making them quickly and easily. Instead of using FRP or some other rigid material, I am now thinking more along the lines of speed and using black construction paper or poster board as the fill material. The center hole and the outer perimeter of the construction paper or poster board can easily be cut with a utility knife, and a hot melt glue gun, will surely bond the balsa frame to the board or paper.
With the fast method now in mind, here are the steps I would suggest:
Cut the fill material (construction paper or poster board) to size and remove the center hole with a utility knife.
Spray a thin coat of temporary adhesive on the backside of the fill material and allow it to dry.
Position and stick the backside of the fill material upon the platform glass.
Construct the balsa frame.
Position the balsa frame within the cut out of the fill material, upon the platform glass.
While pressing the balsa frame firmly against the platform glass, hot melt glue the outer perimeter of the balsa frame to the fill material.
**If the exposure frame does not easily remove from the platform glass, quickly heat the glass until the adhesive is pliable enough to remove the fill material from the platform glass.
To be perfectly honest, I wish I had thought of this method years ago, when I first started exposing PCBs. I would have saved a lot of time.
if you search some of my threads, you will find that I have said many times, "I am not a hobbyist". I am not performing all of these experiments as a hobby, I am performing them so others may enjoy their hobby.
It takes two (or more) to make a conflict. Both of you stop with the personal criticisms. There's enough room in this virtual space for at least two completely separate sets of opinions and neither of you has to look at the other's.
Pertaining to my previous discussion of my new method to make exposures plates, I am now providing a couple of photos, which include two new exposures plates well underway and the exposure plate holder.
The smaller exposure plate will specifically be used to create a power supply switcher circuit board, which controls the power of a wall wart going to the CNC/3D Printer Controller through the use of of a latching pushbutton momentary tactile switch, which is located on the User Interface. The other exposure plate will specifically be used to create the User Interface circuit board. Information pertaining to the User Interface can be located in the controller thread, linked to above. As for the power supply switcher, information and a schematic can be found in this thread http://forums.parallax.com/showthread.php/156184-Discussion-Of-Latching-A-Momentary-Switch-To-Control-A-Power-Supply.
Pertaining to my previous discussion of my new method for making exposure plates, I want to point out that I have deviated from the initial plan. Most changes should be obvious, but most importantly, I changed the balsa wood from 1/4" X 1/4" to 1/8" X 1/4". This will allow for easier removal of the glass weight after exposure.
EDIT: I suppose it is worth mentioning that both of these boards will be double sided exposures.
Here is a photo of the finished exposure plates. I must say that the new method worked quite well and that these plates are the easiest, most accurate, and best looking plates that I have made. Perhaps a little bit of overkill, but I put a coat of paint on them, just to keep the stray light from getting through the glue.
I was striving for frame dimensions which equalled PCB size +0.001, but ended up with +0.001 ~ 0.002, which I am sure is more than acceptacle. I have mentioned accuracy more than once and it is something that I truly strive for, however, in my opinion, the most important dimensions are those of the frame and the positives. The glass weight really does not have to be perfect, but it should be really close. As for the PCB size, unless you are using a CNC driller, it really does not have to be perfect either, but once again, it should be really close. The frame and the positives determine your alignment of the through holes. Closer tolerances result in better alignment and appearance of the final board.
Later today, I will be cutting the glass weights, which will be followed by the PCB material.
When making exposure plates, I occassionally have some trouble with cutting the perfect piece of glass, and such is the case with the "Glass Weight" for the Power Switcher circuit board. As it applies to the exposure plates, the size of the "Platform Glass" is really not all that critical, just as long as it is capable of resting upon some type of support during exposure of the PCB, but the "Glass Weight", should at least extend beyond any of the copper areas of the intended PCB, and preferably to the edge of the PCB, which is what I strive for, although I have not had too many problems when it does not go to the edge of the PCB, except an occassional light bleed. Anyhow, as mentioned, the "Glass Weight" for the Power Switcher has been giving me some trouble, so I thought I would do a little research on glass cutting. Low and behold, I found a very nice document pertaining to the subject of glass cutting. After reading this document, I now know that I must alter my glass cutting technique, and I am providing a link to this document, just in case others may find it useful. The document is titled "The Cutting of Glass", and it is provided by the Fletcher-Terry Company, which is a well known manufacturer of glass cutters. This document can be found here: http://www.fletcherviscom.com/FHandheld/literature/GlassCuttingBasics.pdf
EDIT: As mentioned in Post# 261 and in this post, the "Glass Weight" does not have to be exact, but to avoid light bleeds into the copper areas of the PCB, which is a very BAD thing, it should extend as close to the "Exposure Frame" edges as possible. Idealistically, the "Glass Weight" should in fact be a press fit within the "Exposure Frame" to help ensure good contact of the "Positive Films" against the PCB surfaces. However, this is difficult to achieve.
For the life of me I can't understand all the trouble you are going to to make special tooling and jigs for every circuit board you might wish to make.
The rest of us have been making double sided boards for ages using the most basic of registration between the top and bottom films.
Simply cut a scrap of PC board (of the same thickness as your target board) , about one inch wide, and about as long as the longest side of your printing film. Use thin double sided tape to fasten the bottom of the scrap to the top of the bottom film, about an inch or more outside the PC border on the film. Now put a strip of thin double sided tape on the top of the scrap, and cover it with wax paper. Now place the top film over the bottom film and the scrap, and register them over a white surface, or light box if you have one. Then, while holding the registration, slide out the wax paper, and press the top film to the exposed tape. There, now you have a reasonably robust top and bottom registration of the two films, separated by a "hinge" the thickness of your board.
To use, simply slide a sensitized piece of PC board in between the films, and stick the sandich in a vacume frame and expose both sides simultaneously, or for simpler setups, one side at a time.
If you have no vacume frame then simply use masking tape to fasten the 3 "unhinged" sides of the film sandich to the target board, and expose at will. Everything will remain nicely registered.
Takes all of 2 or 3 minutes, with no special tooling, cutting of glass or other materials precisely to some arbitrary dimensions.
People have said this and that about my method, and even though Leon was a bit annoying at times, he was the only one that ever showed a board that he had made. I wonder why that is?
I have to respect him for that. At least he had something to show for his opinions.
This thread has been running a very long time and there is plenty of room for people to post photos of their work.
Speaking of jigs and referring back to Post# 263 and the subject of glass cutting.
I forgot to mention, in Post# 263, that I previously made a glass cutting jig, to help with making the exposure plates. This jig eventually ended up outdoors and became unusable, so I decided to quickly slap another one together. Before jumping into designing or making another glass cutting jig, I did a little more research on the web, just to see what others have done. I came across a jig which was better than my first one, and it looks pretty simple to make, especially if the T-Slots are eliminated for the stop block. I am currently making something very similar, but I will be screwing my stop block to the table top, instead of having it adjustable. The top will eventually have a bunch of holes, but I do not care, just as long as it serves it purpose.
As it pertains to this discussion and the creation of exposure plates, once an exposure plate has been made, it can be used for a variety of boards. For example, the exposure plate made for the User Interface, has a nominal size of 3" X 4", which happens to be the largest size board that you can develop with the freeware version of the EAGLE software. I can now reuse this exposure plate for any circuit board designed with the freeware that requires the maximum amount of board space. Additionally, I can also design new circuit boards around the size of the Power Switcher exposure plate. For new circuit boards, having the same size as an existing exposure plate, I can simply print out and trim my films, cut some PCB material to match, and I am ready for exposing, without the hassle of aligning registration marks.
In my post on this subject I was not looking to belittle your approach, and certainly not to offend you. But somehow you sure do take suggestions that are not aligned with your approach as offensive, and it really seems to get your back up. I know you are stubborn..... you have said so many times. But why then make all these posts in painstaking detail if you are not interested in other people's comments or suggestions.
All I was trying to do was show a rather obvious and simple method which would eliminate all your many trials and tribulations in making custom jigs for every circuit board you might choose to make. Cutting glass to match a board's dimensions is certainly very odd indeed, and hardly a simple approach.
As to my experience, I first used my described method in 1969, when I started making PC boards, and it worked very well. A little later, and more so over time, my methods became more sophisticated, as I was building a commercial enterprise in making boards for others. Bruce, over the years I have made tens of thousands of circuit boards commercially and for my own production, nearly all of them double sided and through hole plated. Sizes have been from a half inch square through 18 inches square.... the limit of my commercial spray etcher.
So, I believe I do know what I'm talking about, and do not feel compelled dig out an old circuit board to show you. They are better than anything you will ever produce with your (complicated) simple methods. Just look at the frightful over-etching on some of the samples you displayed a while back. While they might still "work", they hardly are quality, eventhough you are proud of them.
While I wish you no harm, I do believe your approach is fraught with difficulty and you will have a frustrating road ahead that you will likely abandon. But then again, you are stubborn, and you may just carry on regardless of how hard you make it on yourself.
Bruce.... lighten up a bit. It's good for the soul, and blood pressure too.
Cheers,
Peter (pjv)
P.S. As a matter of disclosure, I went out of the PCB business about 10 years ago when environmental issues became more prominent, and outside sources became plentiful and relatively inexpensive. I still do some mechanical circuit board "carving" on an XYZ machine when I need a same-day prototype.
I am not opposed to different ideas or methods by any means, because everyone has their own way of doing things, but when someone criticizes me or insinuates that my methods are a waste of time, of course I am going to take offense.
However, your responses come as no surprise to me, because I can go to many of my various threads, and collect the various criticisms and insinuations by you. My work speaks for itself and their are plenty of photos floating around the forum of my handywork and craftsmanship. For all the various negative posts that I have received from you, without any verification of your own skillset, your posts can sometimes be quite offensive. It is so very easy to criticize others, without putting anything the table.
As for what you have done commercially, please don't bore me. Let me see a board that you have made at home with your own two hands and tools. Plated through holes at home, come on Peter, what size was that fish?
Comments
Bruce
For the last couple of weeks, I have been experimenting with several aspects of making PCBs. Through these experiments, I have learned two very important aspects of PCB processing, which are:
- Effectively controlling the temperature of the developer and etchant
- Creating a productive PCB processing environment
By effectively controlling the temperature of the developer, my process has become much more consistent, and by effectively controlling the temperature of the etchant, my etching process has become much more expeditious. Furthermore, as another added benefit of better temperature control of the developer, I can now use a much stronger developer solution, which makes the developing process much more expeditious. At this point in time, I am currently using 12 grams of sodium hydroxide to 1 liter of water, however, I am getting ready to mix up a new batch with a new ratio of 14 grams of sodium hydroxide to 1 liter of water. In the past, I was using approximately 8 grams of sodium hydroxide to 1 liter of water, so this is a very significant increase, and my developing time is much faster.As for creating a productive PCB processing environment, I would highly suggest to get organized. I am now much more organized for processing PCBs, as compared to the past, which has also had an impact on consistency and making the process more enjoyable. There are still quite a few things that I want to improve upon, but it all takes time and money.
To help you in your endeavors of creating your own PCBs, I would highly recommend reading these two threads:
http://forums.parallax.com/showthread.php?139257-New-Project-New-Experiment-PCB-Etchant-And-Developer-Heaters
Construction Of A PCB Prototyping Table
http://forums.parallax.com/showthread.php?139308-Construction-Of-A-PCB-Prototyping-Table
Bruce
Referring to the previous post and pertaining to Philmore DATAK Premier Series positive acting presensitized PCBs, 14 grams of sodium hydroxide to 1 liter of water is way too strong for the developer solution. 12 grams was working good, but I am still seeking the perfect solution for using "ROOTO Crystals of Household Lye Drain Opener" in combination with the Philmore DATAK Premier Series positive acting presensitized PCBs.
At least I now know the ideal mixture is somewhere between 12 and 14 grams per liter of water. As you might have guessed, I will attempt 13 grams for the next batch.
Bruce
Referring to the two previous posts, 13 grams of sodium hydroxide to 1 liter of water seems to be a good ratio for the developer, however for some odd reason, it is making me decrease my exposure time. At 12:1, the premium exposure time was 1:35, and at 13:1, I am currently at 1:20 and still need to decrease the exposure time.
Bruce
Okay, after messing around with 13:1 for a developer mixture on quite a few samples, I am now going to revert back to the 12:1, because the 13:1 seemed just a little to strong.
Bruce
Although I have not been responding, I have read all your posts here and the other threads.
Thanks for all the efforts in documenting this fun project!
Jim
Jim
I sincerely appreciate the words of encouragement, but I must truly admit that it is not always fun. The successes are great, but the failures are torture.
Bruce
Perspective, dude. It's just a hobby. 48-layer boards are being made every day. The solutions (no pun intended) already exist.
LOL. Perhaps for you, but if you search some of my threads, you will find that I have said many times, "I am not a hobbyist". I am not performing all of these experiments as a hobby, I am performing them so others may enjoy their hobby.
Bruce
I am adding this link to this thread for future reference. The method described in this "instructable" supposedly produces nice through hole plating for PCBs.
Well it has been a little over two years since this thread has seen any action, but I came up with a new idea this morning, and I do believe it belongs in this thread.
Since this thread started years ago, I have received plenty of flack pertaining to my method of making PCBs. While admittedly, there has been some challenges and a learning curve along the way, I have slowly been perfecting my method, stategies, and tools. My goal has always been to produce highly accurate double-sided boards. The trouble is that when you want high accuracy, everything becomes more complicated and more difficult to achieve. To make highly accurate boards using my method, which is an exposure frame method, everything must be highly accurate, which includes the PCB board size, the frame size, and the size of the positive or negative image, and today, I will be discussing a new method of making a highly accurate frame.
To start this discussion, let's begin by examining the illustration below, which contains two figures. Figure 1. depicts a cut away view of the exposure frame and the order in which the various components are layered. Firgure 2. depicts a cut away view of the exposure frame, with the various components in place. Although not shown, the perimeter of the exposure frame, tightly surrounds all of the layered components. The inside dimension of the exposure frame should have a little slop, just to allow removal of the layered components. In the past, I attempted a slight press fit, but have since abandoned that method, and I now try to achieve an exposure frame inner dimension of PCB board + 0.001", on both the width and length.
I suppose it is needless to say that it can be an arduous task to get a nice fit with all the various layered components. Since beginning this journey, I would have to say this was the hardest part of the PCB making process. Quality of the traces or pours, is really not all that difficult, once you have the process down pat, but achieving accuracy with an exposure frame method is a pain. As previously mentioned, I am always trying to perfect this method or find an easier way to achieve the accuracy that I desire.
In an attempt to get to the point, the construction of the exposure frame has always been a real pain. Basically the difficulty of making the exposure frame pertains to the material used, accuracy, and the machining processes available. With these difficulties in mind, I have always been searching for an easier way to make an exposure frame. Well this morning, while pondering the problems and possible solutions, I came up with a new idea for making highly accurate exposure frames, quickly and inexpensively. The solution lies in a previous experiment of mine, while reconstructing my PCB saw, and during this experiment, I used JB Weld to cast a critical part. To read about this experiment and the making of a highly accurate PCB cutting saw, please visit this thread: http://forums.parallax.com/showthread.php/156588-Trying-Something-New-Today-My-Latest-Experiment-A-Linear-Slide-Carriage.
From this point forward, I will now be casting my exposure frames, instead of constructing them from various materials. Since there is an endless possibility of various exposure setups, I will not be discussing the finer details needed to accommodate the various exposure setups, I will only provide the basic idea for obtaining a highly accurate frame, or more precisely, I will be discussing my setup. Referring back to Figure 1., my Platform Glass rests within a recess of my exposure setup and the Frame outer dimension has the same outer dimension as the Platform Glass. Regardless of the size of the actual PCB material, this process should be able to work for all my future exposure frames.
The required materials and steps are as follows:
EDIT: As mentioned, I am always looking for a better and easier method. With this in mind, I am now suggesting the creation of a blank made from 1/4" X 1/4" balsa wood, having an inner dimensions that are 0.001" larger than the PCB. I have worked with this balsa in the past and it is pretty easy to make an accurate frame with a disc sander and a hot melt gun. I believe this would be a lot cheaper material wise and it should also be a lot less time consuming. The main difference would be that this blank would not be coated with petroleum jelly and it would not be removed after casting, and in reality, it would become an actual part of the exposure frame, being bonded to the fill material with JB Weld.
To make construction easier, I may eliminate the 0.001" clearance, and just wrap and glue the balsa around the precut PCB material.
As a side note, it should be a breeze to obtain the necessary balsa, considering the largest balsa wood factory in the world is headquartered in the city where I reside
Anyhow, here is a new drawing for this concept.
WAIT!!!
I have another idea..... Simply spot glue the frame to the fill material... Easy, peasy, Japanesey
EDIT: On second thought, the spot glue method is not a good one, because it will allow stray light to pass
In the previous post, I indicated that I would most likely be using FRP as my filler material, which I assume would work just fine, and it would also be pretty sturdy, to allow reuse and the making of multiple PCBs. However, everything I have done to this point, has been one of a kind PCBs and I imagine that trend will continue, although I do like the idea of only making an exposure frame once. Anyhow, for the quick, down, and dirty exposure frame, which would be suitable for one of a kind usage, I now have a different stategy, for making them quickly and easily. Instead of using FRP or some other rigid material, I am now thinking more along the lines of speed and using black construction paper or poster board as the fill material. The center hole and the outer perimeter of the construction paper or poster board can easily be cut with a utility knife, and a hot melt glue gun, will surely bond the balsa frame to the board or paper.
With the fast method now in mind, here are the steps I would suggest:
Classic.
Pertaining to my previous discussion of my new method to make exposures plates, I am now providing a couple of photos, which include two new exposures plates well underway and the exposure plate holder.
These exposure plates will be utilized for making two circuit boards, which will both be used in making my 3D printer. For more information about the 3D printer project, please visit this thread http://forums.parallax.com/showthread.php/154883-A-New-CNC-Build-3D-Printer-El-Cheapo. Additionally, both of these boards will be attached the my CNC/3D Printer Controller. For more information about this controller, please visit this thread http://forums.parallax.com/showthread.php/155404-Input-Needed-Combining-Propeller-Proto-Board-Prop-DIP-40-and-ADC-for-3D-Printer.
The smaller exposure plate will specifically be used to create a power supply switcher circuit board, which controls the power of a wall wart going to the CNC/3D Printer Controller through the use of of a latching pushbutton momentary tactile switch, which is located on the User Interface. The other exposure plate will specifically be used to create the User Interface circuit board. Information pertaining to the User Interface can be located in the controller thread, linked to above. As for the power supply switcher, information and a schematic can be found in this thread http://forums.parallax.com/showthread.php/156184-Discussion-Of-Latching-A-Momentary-Switch-To-Control-A-Power-Supply.
Pertaining to my previous discussion of my new method for making exposure plates, I want to point out that I have deviated from the initial plan. Most changes should be obvious, but most importantly, I changed the balsa wood from 1/4" X 1/4" to 1/8" X 1/4". This will allow for easier removal of the glass weight after exposure.
EDIT: I suppose it is worth mentioning that both of these boards will be double sided exposures.
Here is a photo of the finished exposure plates. I must say that the new method worked quite well and that these plates are the easiest, most accurate, and best looking plates that I have made. Perhaps a little bit of overkill, but I put a coat of paint on them, just to keep the stray light from getting through the glue.
I was striving for frame dimensions which equalled PCB size +0.001, but ended up with +0.001 ~ 0.002, which I am sure is more than acceptacle. I have mentioned accuracy more than once and it is something that I truly strive for, however, in my opinion, the most important dimensions are those of the frame and the positives. The glass weight really does not have to be perfect, but it should be really close. As for the PCB size, unless you are using a CNC driller, it really does not have to be perfect either, but once again, it should be really close. The frame and the positives determine your alignment of the through holes. Closer tolerances result in better alignment and appearance of the final board.
Later today, I will be cutting the glass weights, which will be followed by the PCB material.
When making exposure plates, I occassionally have some trouble with cutting the perfect piece of glass, and such is the case with the "Glass Weight" for the Power Switcher circuit board. As it applies to the exposure plates, the size of the "Platform Glass" is really not all that critical, just as long as it is capable of resting upon some type of support during exposure of the PCB, but the "Glass Weight", should at least extend beyond any of the copper areas of the intended PCB, and preferably to the edge of the PCB, which is what I strive for, although I have not had too many problems when it does not go to the edge of the PCB, except an occassional light bleed. Anyhow, as mentioned, the "Glass Weight" for the Power Switcher has been giving me some trouble, so I thought I would do a little research on glass cutting. Low and behold, I found a very nice document pertaining to the subject of glass cutting. After reading this document, I now know that I must alter my glass cutting technique, and I am providing a link to this document, just in case others may find it useful. The document is titled "The Cutting of Glass", and it is provided by the Fletcher-Terry Company, which is a well known manufacturer of glass cutters. This document can be found here: http://www.fletcherviscom.com/FHandheld/literature/GlassCuttingBasics.pdf
For the definitions of "Platform Glass" and "Glass Weight", please refer to the first illustration of this post: http://forums.parallax.com/showthread.php/135950-ATTN-PCBers-SUBJECT-New-website-and-exposure-box-design-for-your-creative-needs?p=1299808&viewfull=1#post1299808
EDIT: As mentioned in Post# 261 and in this post, the "Glass Weight" does not have to be exact, but to avoid light bleeds into the copper areas of the PCB, which is a very BAD thing, it should extend as close to the "Exposure Frame" edges as possible. Idealistically, the "Glass Weight" should in fact be a press fit within the "Exposure Frame" to help ensure good contact of the "Positive Films" against the PCB surfaces. However, this is difficult to achieve.
For the life of me I can't understand all the trouble you are going to to make special tooling and jigs for every circuit board you might wish to make.
The rest of us have been making double sided boards for ages using the most basic of registration between the top and bottom films.
Simply cut a scrap of PC board (of the same thickness as your target board) , about one inch wide, and about as long as the longest side of your printing film. Use thin double sided tape to fasten the bottom of the scrap to the top of the bottom film, about an inch or more outside the PC border on the film. Now put a strip of thin double sided tape on the top of the scrap, and cover it with wax paper. Now place the top film over the bottom film and the scrap, and register them over a white surface, or light box if you have one. Then, while holding the registration, slide out the wax paper, and press the top film to the exposed tape. There, now you have a reasonably robust top and bottom registration of the two films, separated by a "hinge" the thickness of your board.
To use, simply slide a sensitized piece of PC board in between the films, and stick the sandich in a vacume frame and expose both sides simultaneously, or for simpler setups, one side at a time.
If you have no vacume frame then simply use masking tape to fasten the 3 "unhinged" sides of the film sandich to the target board, and expose at will. Everything will remain nicely registered.
Takes all of 2 or 3 minutes, with no special tooling, cutting of glass or other materials precisely to some arbitrary dimensions.
Cheers,
Peter (pjv)
I am glad you are satisfied with that method. I like mine.
By the way, let me see a board created with that method, that is as small as the samples of Post#1 of this thread.
People have said this and that about my method, and even though Leon was a bit annoying at times, he was the only one that ever showed a board that he had made. I wonder why that is?
I have to respect him for that. At least he had something to show for his opinions.
This thread has been running a very long time and there is plenty of room for people to post photos of their work.
I forgot to mention, in Post# 263, that I previously made a glass cutting jig, to help with making the exposure plates. This jig eventually ended up outdoors and became unusable, so I decided to quickly slap another one together. Before jumping into designing or making another glass cutting jig, I did a little more research on the web, just to see what others have done. I came across a jig which was better than my first one, and it looks pretty simple to make, especially if the T-Slots are eliminated for the stop block. I am currently making something very similar, but I will be screwing my stop block to the table top, instead of having it adjustable. The top will eventually have a bunch of holes, but I do not care, just as long as it serves it purpose.
For a reference design of a glass cutting jig, please refer to this link: http://www.thehobbyist.us/html/strip_jig.html
In my post on this subject I was not looking to belittle your approach, and certainly not to offend you. But somehow you sure do take suggestions that are not aligned with your approach as offensive, and it really seems to get your back up. I know you are stubborn..... you have said so many times. But why then make all these posts in painstaking detail if you are not interested in other people's comments or suggestions.
All I was trying to do was show a rather obvious and simple method which would eliminate all your many trials and tribulations in making custom jigs for every circuit board you might choose to make. Cutting glass to match a board's dimensions is certainly very odd indeed, and hardly a simple approach.
As to my experience, I first used my described method in 1969, when I started making PC boards, and it worked very well. A little later, and more so over time, my methods became more sophisticated, as I was building a commercial enterprise in making boards for others. Bruce, over the years I have made tens of thousands of circuit boards commercially and for my own production, nearly all of them double sided and through hole plated. Sizes have been from a half inch square through 18 inches square.... the limit of my commercial spray etcher.
So, I believe I do know what I'm talking about, and do not feel compelled dig out an old circuit board to show you. They are better than anything you will ever produce with your (complicated) simple methods. Just look at the frightful over-etching on some of the samples you displayed a while back. While they might still "work", they hardly are quality, eventhough you are proud of them.
While I wish you no harm, I do believe your approach is fraught with difficulty and you will have a frustrating road ahead that you will likely abandon. But then again, you are stubborn, and you may just carry on regardless of how hard you make it on yourself.
Bruce.... lighten up a bit. It's good for the soul, and blood pressure too.
Cheers,
Peter (pjv)
P.S. As a matter of disclosure, I went out of the PCB business about 10 years ago when environmental issues became more prominent, and outside sources became plentiful and relatively inexpensive. I still do some mechanical circuit board "carving" on an XYZ machine when I need a same-day prototype.
I am not opposed to different ideas or methods by any means, because everyone has their own way of doing things, but when someone criticizes me or insinuates that my methods are a waste of time, of course I am going to take offense.
However, your responses come as no surprise to me, because I can go to many of my various threads, and collect the various criticisms and insinuations by you. My work speaks for itself and their are plenty of photos floating around the forum of my handywork and craftsmanship. For all the various negative posts that I have received from you, without any verification of your own skillset, your posts can sometimes be quite offensive. It is so very easy to criticize others, without putting anything the table.
As for what you have done commercially, please don't bore me. Let me see a board that you have made at home with your own two hands and tools. Plated through holes at home, come on Peter, what size was that fish?