Diminutive, a small EDM prototype

For the last little bit I’ve been working on a small EDM prototype for use on large parts, pipe sections or for use in the field. While they do make and sell these things, the vast majority of them require the use of vibratory assistance, aren’t terribly accurate and are relatively low powered. I intend to make one that is accurate and could potentially be used as a ram EDM in a pinch. Also, I’d like it to be able to use copper and graphite electrodes so polarity reversal is necessary.

This is the linear drive of the small EDM. It has 8 inches of travel and is surprisingly rigid and play-free. I was going to use a gear motor on the top with a rotary encoder but since the loads are quite small a stepper should be OK, even at higher speeds.

This is the linear drive of the small EDM. It has 8 inches of travel and is surprisingly rigid and play-free. I was going to use a gear motor on the top with a rotary encoder but since the loads are quite small a stepper should be OK, even at higher speeds.

I’m currently trying to come up with ways to mount this guy on magnetic bases but also allow for small amounts of fine adjustment so that if there is a need for precision work, the unit can be dialed in. Right now the coupling is made of two pieces of steel. I’m going to replace one of them with nylon to reduce noise. I was going to use a spider coupler with rubber in between but I didn’t have one kicking around on the weekend when I was making it so I just made my own.

It's all made from 7075 aircraft aluminum. Pretty strong stuff. The movement was initially pretty stiff because the screw, which is just hot rolled, was a little bit out so I had to run it back and forth to wear in the brass acme nut. I may put two acme nuts into the travel block simply to take up play, as it stands though right now there is less tan .0003" of play, even with significant force applied.

It’s all made from 7075 aircraft aluminum. Pretty strong stuff. The movement was initially pretty stiff because the screw, which is just hot rolled, was a little bit out so I had to run it back and forth to wear in the brass acme nut. I may put two acme nuts into the travel block simply to take up play, as it stands though right now there is less tan .0003″ of play, even with significant force applied.

So next things next, the prototype electronics. Right now I’m simply going to use what I have laying around, so a TM1638 display, a cheap chinese stepper driver with a toshiba stepper driver and I opted for an Arduino to drive the motor. I will be making a full fledged PCB that will nicely fit in a box but I need to get the pulse generator and sensory circuits working first, then I can integrate them fully on to one PCB.

Just a rough testbed for the motion control and a simple interface. I would like this thing to be nice and easy to use.

Just a rough testbed for the motion control and a simple interface. I would like this thing to be nice and easy to use.

Well, anyways, I have quite a bit more work to do for this project. Even a single axis CNC can be a little more tricky since it’s doing more than simply positioning. A ram EDM is a dynamic machine that reacts to the sensory input to keep the cut running smoothly and with appropriate voltage and gap settings.

More later.

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Edmonton – Postcards from the past – Part 1

For the last year or so I have been collecting various postcards and images from Edmonton’s past. My collection isn’t that wonderful or anything but I have some neat pictures nonetheless. Since my favorite thing is to do a comparison between then and now, I will also include some Google Earth or Streetview images.

This is an aerial view looking at what was the Edmonton Auto Court. The postcard doesn't specify a year but I can only assume it's sometime before 1953. What we are looking at is 104st southbound going left to right. Where the subject is, the auto court is now where a part of the Scona High School sits. Scona High School was built in 1955 so this was quite some time ago. The little road on the left hand side is 70th Ave. Many of the houses are still there.

This is an aerial view looking at what was the Edmonton Auto Court. The postcard doesn’t specify a year but I can only assume it’s sometime before 1953. What we are looking at is 104st southbound going left to right. Where the subject is, the auto court is now where a part of the Scona High School sits. Scona High School was built in 1955 so this was quite some time ago. The little road on the left hand side is 70th Ave. Many of the houses are still there.

I tried to get the view as close as possible but it's not always possible to change the  field of view to match. As you can see, most of the buildings have been torn down except  what appears to be an old shack in the bottom left hand corner of the original. It's interesting to me because I used to work for the company that grew out of that building. It was called Micro Machine. Also, many of the houses in that area are exactly as they were from that time but the colors have faded significantly. Also, you can spot the remnants of the train tracks that used to run along that path. As far as I know they were moved in the late 70's.

I tried to get the view as close as possible but it’s not always possible to change the field of view to match. As you can see, most of the buildings have been torn down except what appears to be an old shack in the bottom left hand corner of the original. It’s interesting to me because I used to work for the company that grew out of that building. It was called Micro Machine. Also, many of the houses in that area are exactly as they were from that time but the colors have faded significantly. Also, you can spot the remnants of the train tracks that used to run along that path. As far as I know they were moved in the late 70’s.

I find those kinds of comparisons pretty cool. Here’s another comparison from another postcard from the 50’s

This is a view of the Legislature grounds from some time in the 50's. As you can see there is a large building in the bottom right that has been torn down and the auxiliary building that sits on the Legislature grounds is substantially shorter than it is today. There have been a huge number of changes to this area in the last 60 years.

This is a view of the Legislature grounds from some time in the 50’s. As you can see there is a large building in the bottom right that has been torn down and the auxiliary building that sits on the Legislature grounds is substantially shorter than it is today. There have been a huge number of changes to this area in the last 60 years.

A Google earth view from 2014. Tons of changes. As you can see we have a great many more trees, or older larger ones at that but we have ripped up the tracks that used to run along 109st and there are more government buildings.

A Google earth view from 2014. Tons of changes. As you can see we have a great many more trees, or older larger ones at that but we have ripped up the tracks that used to run along 109st and there are more government buildings.

And now, I’ll simply post some images from Edmonton’s past that I have a bit of history on

This is the Hotel MacDonald as drawn in 1915. In the 50's they added an auxiliary building which didn't match the style or grandeur of the original building. It was called 'The MacDonald Hotel and the box it came in'

This is the Hotel MacDonald as drawn in 1915. In the 50’s they added an auxiliary building which didn’t match the style or grandeur of the original building. It was called ‘The MacDonald Hotel and the box it came in’. They later demolished the extra building and restored the hotel to its former glory.

This is from a postcard from the late 1980's as far as I can tell. You can tell simply by the super saturation of the photo. Also, there was a truck stop on the south side of Edmonton on Calgary Trail called 'Mr Johns'. I believe it closed down in the late 2000's due to the construction of a bypass route which decimated the businesses in that location.

This is from a postcard from the late 1980’s as far as I can tell. You can tell simply by the super saturation of the photo. Also, there was a truck stop on the south side of Edmonton on Calgary Trail called ‘Mr Johns’. I believe it closed down in the late 2000’s due to the construction of a bypass route which decimated the businesses in that location.

Anyways, I hope people enjoy these as I have many, many more to post. I may try to research the images a bit more closely and give some history on them.

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Quick post: JY-MCU TM1638 Drawing

Just figured I’d share a drawing I made of the JY-MCU 8 digit TM1638 display for whoever wants it. I love these displays and figured others might like them too.

tm1638 model

jy-mcu display tm1638

REMINDER: I did not include the headers on the front. I usually clip them off because they are useless when trying to fit them in a panel!

jy-mcu display tm1638 (in PDF format)

jy-mcu display tm1638 (zipped IGES / IGS file)

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Summer is almost over

Yes, summer is almost over and it’s been about the whole summer that I haven’t posted anything. That’s not to say that I haven’t been working on anything though. Here are a few of the things I’ve been working on.

Autonomous Submarine

This project hasn’t gone as quickly as I had hoped. I’ve been working mostly on the SONAR portion of it but frankly this summer has been very busy work-wise and thus I’ve been at a loss for getting stuff done. I’ve also been working on a viable, yet inexpensive depth sensor for the craft. For this I have to give a shout out to Farnell/Newark Canada who were kind enough to give me a sensor for the occasion. Visit them at http://canada.newark.com or http://element14.com

The 100 psi sensor that Farnell/Newark sent me

The 100 psi sensor that Farnell/Newark sent me

With this device I can easily keep an accurate depth reading up to my limit of 130ft. Yes the depth is arbitrary but that’s a good depth for most lakes around here. The idea first is to simply plunge the chassis down into the depths and record the images recorded from the main cabinet.

 

A very simple chassis

A very simple chassis

Well, there’s not much to her but perhaps I can get it dipped into a lake before the snow flies.

Some games

Yes, I’ve been working on games again. It’s a fun diversion for a while and it’s been a while since I’ve made anything substantial. Here’s a couple of screenshots

My start at a game called Prellex. Not very good looking yet but I intend to have smart AI take the place of large numbers of enemies to provide difficulty.

My start at a game called Prellex. Not very good looking yet but I intend to have smart AI take the place of large numbers of enemies to provide difficulty.

Another rendition of my old game Reaction. I should probably finish this one since it's a pretty fun game and would work well for HTML5

Another rendition of my old game Reaction. I should probably finish this one since it’s a pretty fun game and would work well for HTML5

Anyways, aside from that I’m working on a basic design for a 2D stepper driven table for use with a stamping head but realistically I haven’t had the time to do anything with that.

We’ll see what the next few months brings!

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Testing out my HTML5 compiler with a game, Flarpy!

It has been a long time since I wrote a game. This one just took me by surprise as I was playing Flappy Birds for the first time. Having heard that the author pulled it. I wanted to make my own version but different.

Pulling from Super Mario Bros. and Flappy, I came up with this. I started writing it at work today and am now finishing up the levels. Hell, I even made a little title graphic.

flarpy

Well, it took me about a day to write the game but the levels are another thing. I will update the game as I finish the levels and hopefully someone, somewhere enjoys this game.

Link to HTML5 game here

Link to small project page here

 

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3D printing, some thoughts and a potential design

Some recent developments, whether they are fruitful or not, have got me thinking seriously about the design of 3D printers, their use and some of their current drawbacks.

Additive manufacturing has come a long way even in the last 15 years when it was just a novelty and not useful for much more than rough prototypes. While 3D printing will probably never supplant ‘subtractive’ methods such as turning and milling for most things, I believe it will be a real boon for strange, esoteric and one-off parts with limited mechanical demands.

This got me thinking about my own design and what I perceive to be some of the issues with current machines all the way up to commercial machines. A couple of those issues are of concern when making a upper-tier hobbyist grade machines for making prototype parts.

These two things are, the effects of gravity on the part when heated or produced, and the effects of uneven heating throughout the process of printing a given part. This will not only increase accuracy but reduce the need for support structures while printing.

Here is a rough pic of my idea for a 3D printer:

A rough mockup of the 3D printer

A rough mockup of the 3D printer

Having a heated suspension fluid eliminates the wow caused by uneven heating and the droop generated from gravity when the part is properly heated. By keeping the liquid level slightly lower than the workpiece you can still generate lattices without the fear of them filling in. The inflow and outflow should be computer controlled via electric pumps and valves, this way the fluid can remain hot without having to heat the whole enclosure. Draining from the bottom will partially help ensure that the cooler fluid is drained first. You could even add a filter to remove detritus.

For the fluid height sensor, I would probably try to tie it in with the nozzle height somehow without interfering with the work envelope. The level would need to be maintained very accurately in order to ensure maximum efficiency. For this sensor I would probably use my old design for a viscometer with the two Piezo discs, instead of measuring viscosity, I would just check for fluid contact, for this purpose it proved to be very accurate and resistant to fouling.

For the fluid, it should match the density of ABS fairly closely. Mineral oil or Propylene Glycol might be good candidates. The idea is to have a fluid that is non-toxic, non-flammable, somewhat viscous and chemically inert with plastics.

Some drawbacks

  • Fragile hollow objects with no holes (a ball) may become deformed due to fluid pressure. though this would require quite a bit of depth to achieve. Not to mention that the item would want to float.
  • Structure needs to be very rigid and acceleration and deceleration needs to be toned down as to not allow the fluid to slosh around which could shake the part loose during printing.
  • potentially messy with fluid being added to the mix.
  • mechanically more complicated and motion components need to be at least resistant to fluid being used.
  • Fluid would probably need to be changed with different materials. A fluid denser than the plastic being laid down may cause issues.
  • Stronger binding to the table is required especially with lattice heavy designs, floating will occur.

Anyways, that’s my idea, posted for posterity. Maybe someone will find it interesting or foolish.

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VariGage moving along nicely

The ugly prototype of the Varigage Circuitry.

The ugly prototype of the Varigage Circuitry.

Well, things are proceeding, slowly but well. I’ve been busy with Christmas and general work and relaxing but it’s time to carry on with the device.

This prototype currently has the following features:

  • An Arduino Mega (will be replaced with a PIC)
  • HD44780 display module, may replace it with a nice flat transflective LCD
  • an ugly keypad
  • Input for quadrature from linear scale
  • Output to DC motor
  • Switching 12v to 5v supply
  • rs485 transciever for communication to the anvil

All of the parts are made but not entirely finished. Going to finish them soon. I was able to assemble them and the actuation is smooth as silk.

Anyways, gonna try to finish the mechanical soon so I can have the ungly prototype up and running. Hopefully I’ll be able to get a finished version ready for the oil show.

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Enough fucking around… The VariGage

Well, After some time thinking about it, it’s time to take things into my own hands and design what I want, the way I want it. Since it’s shortly after my 34th birthday I’ve realized that time is getting short and I have to forge ahead.

Hence, the VariGage. I’ll change the name later but it suits it just fine for now.

The prototype VariGage. Not much to it right now but the implications of a miniaturized version are great.

The prototype VariGage. Not much to it right now but the implications of a miniaturized version are great.

This device will allow for a multitude of gaging options with full communication between the anvils and expansibility. Gagemaker makes something quite similar however, mine differs in a number of ways in both design and use.

  • Affordability, the average machinist should be able to afford a unit to fit in their repetoire. While it’ll be a very expensive tool, it’d be nowhere near the 12,000 bucks or so of the GageMaker device.
  • Anvil communication. The device will communicate with the anvils allowing for future use of anvils that weren’t available upon first creation of the device. also this allows for cheaper calibration of anvils rather than the device itself.
  • The device is motorized. It will position itself to the desired location and hunt when the user is pressing and calibrating a gage on the device. The final version will involve a clutch to allow rapid hand positioning
  • Light weight with modular display design.

These are a few of the differences. The market is completely different from what GageMaker sells. I’m not even completely sure it’s sell able but I simply have to build it. I have a few other ideas and designs I have to get done but this is the first in the line and I think it’ll be very interesting when done. Heck, it’ll be nice to have if I go to another shop even, who knows. :)

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Three years at Rejent!

Well, It’s been three years at Rejent (plus a week). Since I haven’t updated in a while I figured I’d go through some of my Solidworks files and post a few of the things I’ve worked on during my time here. After looking through the files I am quite amazed at how freakin’ many parts I’ve worked on over the time I’ve been here. Hundreds of different things!

Anyways, here are some pics of a few things I’ve worked on during my time here, albeit a very limited selection of them.

That was just a few of them that I randomly found, nothing too crazy since some of I couldn’t really show. Well, let’s see what the next few years brings.

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The project is finished! And other goings on.

I have just finished the project that has taken up the last 3 months. Delivered to the customer and they are very happy with it.

A view from above on the two sizes we made for the customer.

A view from above on the two sizes we made for the customer.

I’m so glad to be done this project. While it wasn’t a terribly long project, I’m glad it all went off without any real problems. It measures better than they’d hoped and it’s a pretty attractive little package, for what it is. Next iterations will be significantly smaller and I will look at new encoders to use.

Also, as an aside I have set up my new office. It’s nice to get out of the basement. I now have a lot of free room now so it’s nice to spread out and be able to sort through all my shit and set it up as efficiently (for me) as possible.

This is my new office for 2013. I have a new computer coming soon.

This is my new office for 2013. I have a new computer coming soon.

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Final version of Digital Gage almost done!

This device is almost complete. Yes, It’s missing its buttons but the device seems to work well and nice and smooth. The real anvils are almost done and the device will ship to our customer fairly soon and I’m glad to see these guys be done!

DigiGage top Digigage from the right Digigage from the top panelThere are still some tweaks to make especially in the realm of overall rigidity but overall it’ll be a neat device to attempt to bring to market in different ways.

 

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An update on the ol’ measuring tool

The prototype gage and the gage ring. looking good so far.

The prototype gage and the gage ring. looking good so far.

Well, it’s coming along with some speed. I am now going to build the final version complete with internal battery charging, better logic and a severe reduction in mass. Hopefully this will go down well with the customer.

The display of the gage. the large 18650 batteries are housed in the right hand side. This will be rectified in later versions.

The display of the gage. the large 18650 batteries are housed in the right hand side. This will be rectified in later versions.

Anyways, this post was for posterity. As always I hope it turns out well. :)

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