My CNC story (part 4)

Please read previous parts first. This is the fourth part of my CNC story. Click here to find part 3, or here for part 2 and here for part 1. I will add more pictures as soon as I have a little time later on.

Abandoning an old computer

When I started with this project my plan was to reuse some old computers I have. One reason for this was that the stepper controller card was, as almost every other DIY CNC controls are, based on parallel port and rely on this port. Parallel port does not exist in modern computers, but all older ones have it as standard. Of course, even modern desktop computers can use PCI cards, so even if the parallel port is no longer standard, that is easily solved even today.

It is worse for laptops, but laptops were not powerful enough a few years ago to drive a CNC anyway, so almost nobody was using laptops, and even today, laptops are rare in this fairly traditional environment.

OK, back to the parallel port

This port type was originally designed for printers, but it turned out to be very suitable to use for many other equipment outside the normal office or home environment.

If a complex machine, like a CNC, is to be controlled by a computer then there is a need for setting different control pins in real time, and those pins are varying in both the total number, and also in timing between different states. Some of those pins (bits) are high or low over a longer period during the work of a CNC than others, some of them, for example the ones giving the step pulses, are pulsing at a high pulse rate and with very short pulse widths, some others, like the step Enable or the Stop signal are constantly on during the whole milling work, but almost none of the signals are synchronous to each other in their state changes. Synchronization is based on needs for the movement, of course if all three (or more) axes must move synchronously then pulses are synchronized, but that is not always the case and is very much dependent on the shape of milling.

Anyway, when milling machines got computerized it was a natural, low cost and a very good solution to use this port. It is simply very easy to control complex machines with this type of port because of the availability of many input, and output signals and the flexibility this port offers.

Nothing lasts forever

Up to and including Windows XP professional, the control of parallel port pins was easy and very flexible for a programmer. However, Windows 7 changed all that, it made it more difficult to set each pins of a parallel port in real time. This type of port became less and less common in computers, today basically not existing in laptops at all, and communication with printers and other peripherals rely on USB interface instead of parallel port. Printers with parallel port are gone from the market, so there is no real need for this port in normal office or home environments.

Some advantages of USB

USB port has many advantages over the parallel port, but when it comes to controlling CNC, it has a huge disadvantage. It is a serial interface, so setting individual bits in real time isn’t that simple any more, not even if one connects a USB to parallel printer port converter to the computer.

To be able to control a CNC using the USB port, one needs a USB motion control interface, which is not only an advanced USB to parallel port converter, but also interprets the G-codes and converts those codes to real time signals, setting the different pins to the levels as needed. In other words, some of the functionality of the CNC software is moved out of the computer and into a USB motion control card because of the loss of possibilities to control individual signal pins in real time through USB.

Some disadvantage of USB

One disadvantage of using USB is, apart from added costs because of the need for a motion control interface, is the need for not just the card but also an interface software, also called plug-in, which interfaces the driver with the CNC software so that the CNC software can talk to CNC stepper controllers. This is necessary unless you have a CNC software which is exclusively designed for the USB motion control card you are using. This plug-in emulates a printer port, so that existing CNC software can be used. Every CNC software is different, so one plug-in which works with one software will not automatically work with another. In other words, the flexibility of use and possibilities of selecting, changing and trying out different CNC software is considerably reduced compared with using the old parallel port solution. Also choosing between Windows or Linux is not possible at all with USB motion controllers, these simply must be designed for the one or the other.

Decisions, decisions…

Using USB definitely has greater advantages then disadvantages, especially when it comes to future computers, so I decided to go for this change and to abandon my old Windows XP Pro based desktop computer, which I intended to use as CNC computer. This saves me a lot of space and offers greater flexibility since with USB I can use any computer, even a laptop, so I can do the design of the milled pieces in my living room, move the laptop to my workshop, plug in the computer and just run the CNC which will mill the pieces.

The old desktop is a dinosaur with the external screen, external keyboard, external mouse and a huge mini-tower case, so the possibility of moving all that functionality into a small laptop is really nice and offering great flexibility.

The decision is made in December 2014. The old computer is out of the loop and USB will be used. Of course, this meant some design change… again…


Please continue with reading part 5.

My CNC story (part 3)

Please read previous parts first. This is the third part of my CNC story. Click here to find part 2 and here to find part 1. I have started to add images, will add more later on, please revisit the pages.

Restarting and full steam ahead

The project was halted but not really abandoned, and in November 2014 I stumbled across an eBay seller who sold the same type of aluminum profile I actually wanted to use, but originally found too expensive to use for a risky DIY project, like building a DIY, self-designed CNC without prior mechanical design and practical experience.

This seller is selling it at a very reasonable price; he is located in Germany and is very fast in delivering, so I contacted him, gave him all the dimensions and asked for a price for all the listed mechanical parts I wanted. After some conversations I placed my order. Delivery was as expected, very fast, it only took a few days, all pieces cut exactly to the length I wanted, even if not all cuts were exactly at 90°, the parts were fully usable and easily aligned to  90° using the joints I also ordered, and definitely better than what I could have done on my own.

He also sold fixtures, screws, T-nuts and everything else I needed for a better design and quality than my first creation would have allowed.

By December I was back on track. This sudden design change made the mechanical work much simpler and considerably better, so I expected to have the CNC ready and working by the end of December, or at latest beginning of January. I have no milling experience, so I knew I will need some time to learn the entire “how to…” part, but at least for this adapter, the V1-F1A flash adapter, I expected that this practical learning will be quick once I have the CNC up and running.

It turned out that I was a bit optimistic about the time. I was doing good progress, but by the end of December I only had the base, a working X axis and a working Z axis ready. On this picture the Z axis is on the floor to the right of the main frame.

Never the less, I was quite happy about how well the work went on, and since the X axis was really running nice regarding the movement and the accuracy, I was now convinced that I will be able to finish this project one day with success.

Next mistake…

As very common in DIY projects, ideas pop up and design changes are sometimes made suddenly. One such change was generated by an idea to improve my design and to build in the control box and the power supply, so that I could skip two extra boxes. I also had an idea to include the power supply for the spindle motor as well, making the machine a bit larger in height but reducing the total volume and space it needed in the end. This change would reduce the cabling and the number of external boxes, so in theory, it was a very good idea. The only bad thing about it is that it meant I had to spend time and work with moving the electronic parts and place everything on top of the CNC base frame, in the Y beam holding the Y axis.

“If it ain't broke, don't fix it.”

This is as true as it can be. What seemed to be a simple change, yet a huge improvement, created a lot of extra work. It took several weeks to get everything up and working again but it was too late to reverse back the process when I realized this simple truth.

Another mistake was…

...adding new functionality.

I decided that some supervision is needed to be added. Now that I moved the electronics I got a huge front panel with enough real estate to add some instruments to supervise critical currents, voltages and temperatures. While this was also a very useful improvement and was fairly simply to implement, it took some extra time and pushed the start-up further ahead. Never the less, I went for it anyway because I was convinced that either I do it now, or it will never be done and that this design change will definitely add positive improvements.

A new set back

In the end, when the electronics were fixed and everything seemed to work well again I realized that I made yet another mistake.

The Y beam holding and driving the Y axis and carrying the Z axis could not share the same beam which holds the electronics, because the stepper motor driving the Z axis would not have enough free space to move along the Y axis. This could be fixed in two different ways, one by adding some extra spacers to move the Z axis away from the electronics, or another by adding an extra, dedicated Y beam. There was a third option also, which was to move out the control electronics into an external box again, like in the original design, but I did not want to do that, so I went for the second solution because it gave me better options for any future changes. For example replacing the control electronics and relocating it somewhere else is much easier this way than if the Y beam has shared functionality. Anyway, this meant I had to start drilling and sawing again, wasting some more time. If I would have kept the original idea and the control box would have been kept at version 1 as a separate box then these two delays wouldn’t have happened and I’d be almost ready by now.

The timing plans of the project is definitely wrong

The delay is now more than a moth compared to my original hopes about making the first cut already at the end of December 2014. At this stage, it is February 2015, but I am definitely doing progress and the improvements/changes are well motivated.



Please continue with reading Part 4.

My CNC story (part 2)

Please read the previous part first. This is the second part of my CNC story. Click here to find part 1. I will add pictures as soon as I have a little time later.

The first (but not the only) observed problem

One issue I discovered was that the motors occasionally skipped steps and/or added extra steps when they were running. Reducing the speed helped, but the problem with the extra steps and the skipping was not solved before the motors were slowed down to totally unacceptable low speed. I simply needed to do something; otherwise it would be pointless to build. Of course, I could easily identify the source of the problem, it was the controller card. I complained to the seller and he/she was kind enough to send me a new card. Unfortunately that meant another month wasted in waiting.

Mechanical works

In the meantime I continued with the mechanical design and buying some mechanical parts. During this process I realized that my home machinery is not enough, I had to buy some new ones or complement the ones I had. One of the things I did was buying a drill press stand, so I could drill straight holes repeatedly. This sounds basic today, but my limited mechanical experience didn’t make this clear for me before I started drilling holes in a larger scale.  The other thing I realized that to be able to drill with accuracy, the bench drill must stand on a very stable stand, preferably fixed to the floor, to avoid vibrations.

Work space, bench and tools

My space in my tiny home workshop is very limited, so I had to build a work bench especially made for that limited space. I attached it to the walls and fixed the bench drill stand to the bench so there is practically zero vibration when drilling. So, if any of you ever start a CNC build project, check out your work space first, check all the tools and machines you have, buy or make a steady work bench and a good drill machine. You will also need a circular saw capable of sawing the materials you are using for the frame and the other parts, which in my case is mostly aluminum. Of course, cutting plastic parts, steel and stainless steel parts is also necessary, as well as grinding and polishing things, so the machines don’t end up with a drill machine and a circular saw. Not only that, but small things like a good set of high quality drill bits and other small tools are also necessary to buy, and while individually they don’t cost a lot, adding them all up makes it into a nice sum. So, don’t start a CNC build project if you are not prepared to pay for all that, unless you already have a well-equipped home workshop.

The new controller card

After five weeks waiting my new controller card arrived. Initially I was very happy and couldn’t wait for plugging it to the motors, but my joy was quickly killed because it had the same problems with skipping and/or extra steps. I thought my analysis was wrong and was convinced that something else caused the issue. It didn’t take long to google and find forum sites where this card was mentioned as a card with very serious problems, similar to mine. So what’s next? I didn’t want to buy a new and different card, because there is no warranty that those would be better, I may end up with similar or different problems with a new card as well, only at even higher costs.

Solution to a real problem

I knew that I have a very high electronic knowledge and could fix this card, so I started measuring and documenting the work. This took quite some time, but have to admit, was challenging and interesting. In the end, I ended up with a total redesign of the card.

This can’t be true, was my first thought, so I did some more googling and found a site called CNCzone, where there was a long thread about this card and how people ended up with the same problems and found different solutions. Most people have given up, but some more or less redesigned the card, made a lot of changes to make it work. Some of the proposed changes were contradictory to others, some were directly wrong, so in the end, I trusted myself most, adopted only very few new changes from that forum since most of my redesign was right and was also implemented by some of those people. Never the less, it was great to find that site and useful to see that I was not alone. Anyway, the time went by and I continued building, concentrating on the control box and other electronics and learning all about programming CNC, using G-code and what it should be able to do.

Mechanical problems

After a while, and well after I was ready with the electronics, I got stuck with the mechanical design. I realized that regardless how I do it, with the aluminum profiles I was planning to use it will be too weak and I will not be able to get the precision I needed. Buying other type of profile would increase the costs to a level which I regarded far too high to make it worth making it, so the project stopped and was put aside.

Though, a few months later I started to see the light at the end of the tunnel.


Please continue with reading Part 3.

My CNC story (part 1)

Introduction

This is the first part of a long story about my DIY CNC project. I hope many of you will find it interesting to read and will have the patience to follow the articles.

I have been actively busy with this CNC project for over 1.5 years now, in parallel with the V1-F1A and other DIY activities. I thought that making a CNC is a fairly easy task for an engineer, but I have to admit I underestimated the efforts. There were several unexpected issues involved which caused a halt or serious delay.

I started off with some reading ups and pre-study. I have electronic and computer science knowledge but no mechanical engineering, so the first step was to collect some ideas, look at what other people have done and try to learn from their mistakes. I knew the accuracies I needed, and I quickly realized that most DIY CNC are not suitable for my needs, at least not in theory. Once I was ready with the idea in my mind, I made some drawings, looked at different possibilities and tried out different ideas on paper and so on.

In the meantime, like so many others, I ordered a kind of a kit from an eBay seller whom I found reliable. The kit consisted of three stepper motors, a controller card and a power supply. This was what I thought, a major step forward because it allowed me to become a “spinner”. A “spinner” is a sort of derogatory nick name among CNC builders for a person who buys motors, controllers and power supply and starts spinning those motors… and NEVER stops being a spinner, never takes the next step, and mainly, NEVER becomes a “miller”. A “miller” is a person who have built his CNC and started milling, doing some useful stuff with it. So while seeing the motors spinning gives a real kick, becoming a “spinner” is a nightmare, not very encouraging.

Today I believe that those cheap Chinese kits are one reason why there are quite a few spinners among CNC builders. These kits can put you to a halt, caused by serious problems, which if you don’t have enough knowledge you will never be able to solve.

My advice is: don't ever buy those cheap kits if you plan to build a CNC unless you have all the time in the world AND the knowledge to fix every problem, because no doubt that you will end up with many problems or need to make serious compromises. In the end, I managed to fix all the issues and problems, but I ended up with a completely different CNC compared to the one I originally started off with, and it took time... a very long time.



Please continue with reading Part 2.

The future of the V1-F1A flash adapter

Thank you all for your interest in the V1-F1A adapter. I really appreciate all the pressure through messages and mail and that I receive a lot of enquiries about the V1-F1A flash adapter. I feel obliged to update about the status.

Unfortunately, as you know, all the adapters are sold. They went very fast, which was a bit unexpected since I made no secret about this not being an industrial product but the result of a do-it-yourself hobby activity. This is good for me, because it shows that I was right, there is a need for such adapters, but it is not good for those who want to buy but cannot get it because it is not available. My intentions are to continue making this adapter again as soon as possible.

I am currently busy with another DIY project, so it will take a few more weeks before the adapter becomes available again in larger quantities. I am currently building a CNC (a computer controlled mill) which will help me making this adapter, among other things, in higher quality and quantity than otherwise possible. This activity took a bit longer than expected but it is progressing, so don’t give up hope, the adapter will be available again.

I receive a lot of mail from people who want to buy the V1-F1A flash adapter and for those people I can only say, please be patient.

Now and then I also receive mail from people who are interested in the “inside story” to find out HOW to do the adapter, which pins to connect and so on. Some offering their “help” and/or want to do it on their own, more or less expecting me to give them the information I worked out on my own. To those people I can only say I am sorry, but no, this information will not be made public by me.

I am sorry, but I am not ready to help out anyone in making the modifications of a Nikon 1 flash, or a GPS on your own or explain how to make an adapter. I invested a great deal of money in this, bought quite a lot of special tools, burned one camera and one flash in the process, and also spent a lot of valuable time in gaining knowledge about how to do it. So, I hope that all of you understand that I intend to get back at least some of the investments. This adapter exists only because it is a DIY project and because I am technically well-skilled and I am interested in understanding how things work. If it was an industrial project with the aim of making profit it would have been stopped a long time ago, before it ever hit the market. If I'd publish the information and the way to design the adapter then I'd not be able to sell more of these, so that is not an option for me right now. I am sorry, and hope you understand my position.

I also receive mail from some people who actually want to buy the information. Again, the answer is no, the information is not for sale.

Please note that the new version is now available. Read about the details here:

http://adapting-camera.blogspot.se/2015/08/the-v1-f1a-is-dead-long-live-v2-f1a.html

Some comments from users of the V1-F1A flash adapter

I receive a lot of mail and comments from users spread out in many countries. I took the liberty to compile some of those comments extracted from the mails. I translated the Danish to English but otherwise not changed anything.

If you are interested in this adapter and want to see more detail then just follow this link:


http://adapting-camera.blogspot.se/2014/10/introducing-v1-f1a-generic-flash.html

Comments from USA

"Thank you very much. It's a very nice solid fit. Just thought you might like to know I was also able to sync my flash with a Yongnuo 2.4 Ghz popper at 1/400 with no banding."
 
"I applaud you on what you managed to do in creating the V1-F1A."

Comments from Denmark

"Den adapter gør det meget nemmere at sætte en radiotrigger til studio flashes på. Det er fantastisk, at du har gjort det store arbejde. Tusind tak for adapteren!!!"

"SB-700 og sync kabel. Virker perfekt op til 1/400 med mekanisk lukker. Yongnuo RF-602 med speedlights sync’er op til 1/200 mekanisk. Elinchrom studio flashes med Elinchrom trigger sync’er op til 1/250 men har først fuld lysstyrke fra 1/200 og langsommere. Det er det samme når jeg trigger dem optisk. Så alt er helt fint, som det skal være."

Translated to English:

The adapter makes it much easier to put a radio trigger on the camera for studio flashes. It's great that you've done the hard work. Thanks for the adapter!!!

SB-700 and sync cable works perfect up to 1/400 with mechanical shutter. YONGNUO RF-602 Speedlights sync up to 1/200 mechanically. Elinchrom studio flashes with Elinchrom trigger sync up to 1/250 but reaches first full brightness from 1/200 and slower. It's the same when I trigger them optically. So everything is just fine as it should be.

Comments from Poland

"It's awesome that I found your video on Youtube."

The two video he is referring to are these two, in case you have not seen them.



 

Comments from Spain

"Everything perfect. I've tested and works great.
Thanks for everything."

Comments from Italy

"I wanted to warn you that the material has arrived in perfect condition, and very well made.
I remain convinced that in any case you've been really good at thinking and realized this adapter. Thanks again. I wanted to tell you that you have been really great to create this adapter, no big brand accessories has designed it, and have found it really salvation."

Comments from UK

"I did indeed sort out the issue and it was one of config settings on the Pocket Wizards Mini TT1 - Flex TT5. These units can be programmed with 2 switchable profiles so now I have one for TTL when using Nikon speed lights and the other is a pure trigger."

"Once again many thanks for your prompt service and support."

Almost all the adapters are sold...

Since I sold all the readily made adapters and since quite a lot of people are interested in buying this, I decided to assemble all the adapters I had parts for. This was last week... Now I have only one ready to be delivered and have parts for two more. That's all. After these three I will not make more of these until I have finished my next project, a CNC which I am in the process of building partially for the purpose of making these adapters and similar, unusual things or equipment you can't find elsewhere.

So, keep tuned in and follow my projects. In the meantime, three more people can buy the V1-F1A already this year, the rest of you must wait and hope that my CNC will work as I expect it. I will keep you informed here about the CNC project status as well, as soon as I have time, I will write about it.

Anyway, so far so good, I have all the electronics ready and tuned, have all the motors which I will use and almost all the mechanical parts needed, so the works has not just started, it was ongoing since over a year now.

If you are interested to buy the V1-F1A adapter then follow this link for the details:

http://adapting-camera.blogspot.se/2015/08/the-v1-f1a-is-dead-long-live-v2-f1a.html

Possible shutter speeds when using the V1-F1A flash adapter

If you are using the V1-F1A flash adapter it is important to know the maximum usable shutter speed. Going outside the limits may result in a black band (shading). Since the camera is not recognizing the flash it has no idea about how to handle it. The V1-F1A adapter allows you to select any shutter speed so it is up to the user to select the one which is suitable for the situation. Setting too low shutter speed may result in motion blur, setting too high may result in black band. How large that band is depends on the shutter speed, the higher the shutter speed above the maximum usable the wider the black band.

Additionally, the electronic shutter behaves different from the mechanical shutter, not only in terms of maximum shutter speed, but also in terms of shutter movement. The shutter blades move the opposite direction, from the bottom up, as opposed to the electronic shutter, which emulates the mechanical but with a movement from the top down to the bottom of the image. This is clearly visible in flash images taken with shutter speeds above the maximum usable shutter speed.

The above is demonstrated in the following images. I used the V1-F1A adapter on the Nikon V1 which triggered an Olympus T32 flash in a grip, as seen in the image to the right. The grip is necessary because the flash is too heavy, so it is not suitable for direct use in the adapter. The test images are taken from about two meters and the test subject is a full size Venetian mask on a white wall.

Electronic shutter

The electronic shutter has a sync speed of 1/60s according to the manual. This is confirmed during my experiments, the maximum usable shutter speed is 1/60s regardless of which flash I have used so far, going above that will result in a black band.

With the shutter speed set to 1/60s the camera captures the full image area.

Already at 1/80s, which is only 1/3 stop above the specified flash sync speed there is a visible black band at the top of the image.

The black band is growing rapidly as the shutter speed is increased. This image is taken with 1/100s shutter speed.

At 1/125s almost half the image is covered by the black band. 

This is taken at 1/160s, more than half of the image is now black.

The last one with the electronic shutter is taken at 1/200s shutter speed. This is the highest shutter speed with which the camera still triggers the flash. At higher shutter speed there is no trigger signal out of the camera and the flash is not triggered.





Mechanical shutter
 

The mechanical shutter is in many ways better when a flash is used. One reason is that the specified sync speed is much higher than with electronic shutter. This is possible because the shutter movement is much faster than the electronic shutter is capable of emulating so the shutter blades can expose the full image sensor area at higher shutter speeds.

This is taken at 1/250s shutter speed, which is the documented maximum shutter speed with flash, also called the flash sync speed. 

This image is taken at 1/320s shutter speed. The camera still manages to handle the flash, the shutter is fully open at this speed. No shading, or black band is caused by the shutter blades.

This image is taken at 1/400s shutter speed and still no shading, a fully usable image.

Shading starts at 1/500s. With the mechanical shutter the shading is from the bottom up and the band does not have as clear edge as with the electronic shutter. This is because there is a distance between the actual shutter blades and the image sensor and this is normal for mechanical shutters. 

Shutter speed: 1/640s and the shading is now significant.

Shutter speed: 1/800s. ...and so on, until at 1/2500s almost nothing is visible, except a very narrow part of the image. After that the flash fires too late and only a black image is taken.

Conclusions

The Nikon 1 V1 can be used only up to 1/60s shutter speeds with the electronic shutter, just like it is specified in the manual. With the mechanical shutter, even though the manual specifies 1/250s shutter speed as maximum, in reality we can use even 1/400s without any negative effects.

Please note that the above conclusion is only valid for my flashes and my camera. I don't know if every camera or even the Nikon V2 and the Nikon V3 behaves similarly, or if this is valid with every other usable flash. I tested with the Olympus T32, the Osram VS280 Studio, Metz 30BCT4 and Sunpak Auto zoom 3000 flashes. 

Please note also that the above is only valid through direct connection. With a radio trigger the trigger sets the limit as well and my radio trigger works only up to 1/250s, above that speed there will always be shading. 

If you are interested in buying the V1F1A flash adapter or want to know more about it, please follow the link below.

http://adapting-camera.blogspot.se/2015/08/the-v1-f1a-is-dead-long-live-v2-f1a.html