Another improvement

As you might remember, I have a prusa i3 on loan, and had an issue with the cables to the servos breaking due to the movement of the axis. You can read all about it here.

Consequently, when building the Blocks Zero printer, I payed particular attention to the routing of the cables, and securing them such as to avoid excessive stress at the most fragile point, i.e. where it enters the connector. The problem is that the movement induces fatigue at the point the cable joins the connector pins.

It doesn't appear to be such a big problem in the Blocks Zero, as only one servo moves, and moves along with the Z axis, making it not too mobile. Still, I decided to make a jacket for it, to hold the cable slightly above the connector, to maintain the cable/connector connection free of movement.

This is the result:

Again, the printer is so accurate that I first printed a part with an extra 0,5mm tolerance, and it was too loose. I ended up printing one with the exact 42mm.

As usual, the models can be found at the warehouse.

Blocks Zero 3D printer

A few months back I ordered a Blocks Zero 3D printer in kit. It appeared to be a nice printer, made in Portugal!

Received it and finally had the opportunity to assemble it after the holidays.

What a great little printer it is! Great build quality, great assembly instructions, and everything worked right out of the box!

Go check it out! and if you need a small printer - it will only print 12x14x12cm in PLA - I think it is a great contender!

I ordered a heating plate to install a warm bed to be able to print ABS, but I'm not sure I'll install it. At least not now. It just runs so well and produces such nice parts that I'm not sure I want to change it.

If you do assemble one, be sure to check the additional assembly instructions at their website, which I wasn't aware until after I figured out how to assemble those extra parts.

Here are some pictures of the final product.

Once I finished assembly, I wasn't very happy with the black display being left there in the hole, so I designed and printed a little frame for it, which I think really ties the whole thing together. And the precision on the printer is so good, that it fit right in. It's a tight fit! It was a bit difficult to take it out from the base plate, and it broke a tiny bit, which I glued back in place. Might print another one soon.

The files can be found here on the google warehouse.

I would advise to remove the display for installing the frame.

Prusa i3 improvements

As I've been posting here, I have a prusa i3 on loan for a couple of months.

A few weeks ago, I got a piece that had no plastic deposited on one specific area, and was fine on the rest. This was very odd, so I had it reprinted and stayed around to see what happened. Immediately I saw that the extruder stepper motor was not turning. I looked around to try to see the reason for this, and found the culprit: a damaged cable:

Extruder stepper broken cable

I tried fixing it, by taking out the small metal tab in the connector, but that didn't work for long.
I talked to the owner of the printer and he had a spare cable. According to him this had happened before, and was a common problem.
The issue here is that a lot of stress is put on that particular cable as it travels left and right along the X axis all the time, plus vertically, although that is a slow and much less often travel.

Since I don't like problems that reoccur, I thought of a solution: a cable holder that transfers the stress from the connector to the cable, which is a point much less prone to failure. So I designed a cable holder that holds not only the extruder stepper cable, but all the cable for heating the extruder and for the fans. Here it is, printed in glow-in-the-dark PLA:

Extruder stepper cable holder

Extruder stepper cable holder

This makes the whole cable behave much better, and I think will also prolong the life of the extruder heating connections. I also printed one for the X-axis stepper motor which travels up with the Z-axis:

X-axis cable holder

You can find these models in the warehouse here.

While discussing this problem, I also realized the cable proving the heated bed with power also keeps traveling back and forth along the y-axis and so it would also fail sooner or later, so I also designed a little holder for this. You can find it in the warehouse here:

Heated bed cable holder

3D Printed zipper fix

I have been very busy with the 3D printer, and have a lot of pictures and material to post here, so stay tuned!

Today it's about a little fix: a broken zipper on my daughters favourite backpack.

As you can see in the picture, the zipper handler was broken, but she was still using the backpack, however difficult it was to open it.

The broken handle

This hardly asked for a 3D printer to fix, but, since I was busy printing stuff, why not print a handle for the zipper? So that I did.

The handle, in glow-in-the-dark PLA

I then used a dremel to cut a groove on the printed PLA (glow-in-the-dark) part, and used epoxy to glue it on.

This is the final result, she is very proud of it, and of me having fixed it, and she loves that it's glow-in-the-dark!

The handle glued in place

Chimney Turbine fix

Another unconventional fix, this time the chimney turbine.

The Chimney Turbine

It's been there for a 4 or 5 years, rotating steadily and stealthily, until a couple of nights ago, it nearly drove me crazy as I searched for the origin of a faint noise as I used the computer in the attic. I thought it was from the hard disk, then the boiler, and finally, after a night or two I realized it was from the turbine. It didn't help that there wasn't much wind, so it only turned intermittently.

Come the weekend, and I jump on the roof to get it out, disassemble it, to find a rusty bearing at the very bottom. The hole where the axle is assembled is protected from water ingress, but I guess not protected enough, and over the years, some water accumulated, and got the bearing rusty.

The rusty bearing

A trip to the local hardware store later, and I ordered the bearings on eBay, from some German store. The local store closed at 12:00 on a saturday!

The rusty bearing opened and the new one about to be installed

They arrived today, so I prepared it all, ready for final assembly and replacing it on the roof!

CF to SATA adapter fix

Some time ago, I bought a motherboard (ASUS AT3IONT-i) and a large disk for a project I had in mind. It was the first SATA disk I ever bought, so I was curious as to how that worked.

Plugged it all, and the disk did not work...never got recognised. Strange.

After a lot of investigation, and blaming it on the disk, I remembered I had a CF to SATA adapter lying around bought in a trip to Taipei's electronics area, so decided to give that a try, to rule out the disk.

As I plugged it in, smoke! from one of the regulators. Very strange. Upon some quick investigation, I found out that the 5V and the 12V lines on the power cable were switched, the one that came with the Motherboard. I was upset and thinking of how would they look at me in the shop if I show up with such an argument, that the lines in the cable are switched.

But it was late at night, and I wanted to get it done, so I just disassembled the cable and reassembled it properly. Unfortunately, no pictures of that. All was well afterwards! Except for the adapter that was burned.

So last time I ordered something from Conrad, I remembered that, and ordered some regulators of the same kind. Tonight I did the switch! exciting, as they are SMD components, but it went much easier than expected! Here are some photos:

Burned regulator, AMS1117-3.3

 Regulator removed

New regulator in place!

Now the adapter will go into the black hole of computer components, never to be used again! but at least it is fixed!

Garage door fix

This past weekend I went to dump a lot of the stuff I collect in my garden into the garage. It opened, I dumped all the stuff, and then, when I pressed the button on the remote to close the door, it did not close. Since the door is a bit rusty, I thought that it could be stuck. It wasn't. I tried to force some the movement, it did not move. I released it from the rail, and tried to get the carrier on the rail to move, no success. My neighbor, who is a part time mechanic in the local shop, was passing by, so I asked him, he looked at it, heard it, and suggested that the gears might be worn out. Conclusion, I probably needed a new machine to open and close the door.

So, since there was nothing to loose, I decided to open it up and check if there was something that could be blocking the mechanics of the thing.

Started to take it apart, removed the cover, the motor, a 220V asynchronous I believe (winding in the stator), looked great. Here is a picture of the machine without the cover, sorry for the quality of the pictures, goes to reinforce my disbelieve in mobile phone camera quality...

Fig. 1 - Machine with the cover out, the electronics are still in on the left, where the open cover is

I then saw the electronics compartment, which could be removed by disconnecting the cable headers, so I took it out to have a look, at least out of curiosity.

Then I started looking at it, and realized that there were 2 relays, luckily transparent, which looked a bit dirty, and started to trace how the circuit worked to control the motor.

Fig. 2 - Dirty relays, you can clearly see the sooth, and although the lower one is dirtier, the malfunctioning one was the top one

Fig. 3 - Another view. The machine was tested (geprueft) in March 1990, that is 21 years ago, I hope it will last another 21!

I replugged the electronics and pressed the buttons to see what happened. When the electronics were in the "door opening" mode, all looked well, when in the "closing door" mode, there was a lot of sparking in the relay. So I knew there was a problem there.
I ran to my favorite local electronics supplier - I am lucky to have a nice little shop literally around the corner (3 minutes on the bike) where the guys have all the necessary electronics components, and know their stuff!

So I went there, and after a discussion on the behavior of the relays, which could indicate other failures, we agreed that it could only be the burned contacts. He then disassembled the board to check the pinout, and gave me two new compatible relays!

I came home, removed the old ones, soldered in the new ones, and ran to the garage to try it out.
The result, a nice working door again!

Fig. 4 - Two old relays, one of the legs is missing, so I had to do the same to the new relays.

Fig. 5 - The PCB without the relays. The power adapter is 2x9V, so the relays are being driven at 18V instead of 24V, that might also not be good for the lifetime of the relays (me complaining about something that lasted 21 years)

Fig. 6 - The new beautiful baby blue relays in place and ready for action. Now with blue relays instead of the boring beige transparent ones, the machine looks like something from this decade! maybe I should change the green LED by a blue one to really bring it into the 21st century!

I then decided to change the lock as well, since I did not know where the real key to the garage was (never used the real key since we bought the house) and if the machine would fail with the door closed, I would be in trouble. So that included a late minute run on the bike again to another nice little locksmith, which knows me by now, and always has the right supplies! Of that fix I did not take any pictures...sorry...

I was very proud of my fix, finally the electronics practice with the little projects around the house payed off! 11 euro to fix the garage opener, instead of a new expensive one! Furthermore, I now found the user manual of the machine, a Marantec 100 confort, which, since it is german and from the early 90's, it is complete with a circuit diagram, which enables me to build a new controller if I so wish, maybe one with JeeNodes and solid state relays for reliability (more on that when it comes to the RFID lock!)