Powerhouse Museum – Mummies, Rockets, 3D Printers

This weekend just gone I visited the Powerhouse Museum in Sydney. Currently, there is an exhibit of several Egyptian Mummies from the British Museum’s collection. The exhibition wasn’t too bad and there were plenty of amazing bits and pieces on display. (The British Museum has “acquired” quite a collection of Egyptian antiquities).

Personally, I don’t quite get the appeal or understand the need to know such excruciating detail about how these people lived and died 3000 years ago, but its not everyday you get to see something that old. (Will people in 3000 years really care so much about how we are currently living?) Anyway, entry into the exhibit also gave access to the rest of the Museum.

If you’ve never been to the Powerhouse Museum, its Sydney’s museum dedicated to technology and applied science. I’d recommend visiting the museum if you’re ever in Sydney. If you’ve stumbled across this website, then I’m sure you’d be interested in the museum’s exhibits. Continue reading

More PETG Setting Adjustments

So far its been almost two weeks since I started using PETG and I’ve resolved a lot of the problems I was experiencing in my last update.

Bed Adhesion Perfected

My prints are no longer becoming completely stuck to the print bed. Now, I can easily peel the completed print from the bed once it has cooled to about 45°C. Removing the print is almost trivial in how easy it is to do.

To achieve this, the first layer settings are very different to that of ABS. Smearing the filament into the bed is the wrong approach. It leads to nozzle jams and adhesion that causes the print to break. Instead, I have found that a first layer height of 105% of first layer thickness is needed. The extruded filament literally is laid down onto the bed. It looks as if it has no chance of adhering, however it is working perfectly.

Return of the Jam

After waxing lyrical previously how I’d fixed my nozzle jams by increasing the first layer height and reducing print speed, nozzle jams returned. They became quite significant. I was about 50% of the way into a print when they began occurring and I tried to salvage the print. Each time a jam occurred, I’d pause, remove the filament, cut the damaged filament off and insert it again and continue on. Continue reading

PETG Filament on a Da Vinci – First Thoughts

I have just begun printing from a brand new roll of PETG filament on my Da Vinci 1.0. Several reviews suggest that PETG is almost a hybrid of ABS and PLA.

I’ve used ABS for the vast majority of prints and whilst I have my printer printing ABS well, some of its properties frustrate me. They are; smell, poor bed adherence and warping.

PETG is meant to address the issues of warping and bed adherence.

My first print with PETG has been somewhat successful. Bed adherence was excellent; the filament printed straight to a clean glass surface that was heated to 80°C (the nozzle to bed clearance is 0.25mm). There was no warping or lifting of the print at the edges and the smell was not noticeable (I’m sure just because I can’t smell anything doesn’t meant there are emissions that are not good to be breathing).

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Status Update and Random Links

Apologies for the long wait between drinks folks, however a few things have been taking up my time; supervising 2 construction  projects at work, then starting a new job, as well as buying and selling an apartment.

To sell my apartment, I’ve had to pack up my 2nd bedroom that doubles as a workshop to prepare for all the house inspections. People who don’t spend their time building, making or tinkering with stuff wouldn’t have a  workshop as a high priority on their list of “Pros”. A friend agreed that I needed to pack up my workshop, he politely noted, “It would be hard to visualise that room ever being a nursery”.

So, I’ve been without a means to build, break, print or experiment with stuff for about 8 weeks now and it has been frustrating. To fill the void, I’ve spent a lot of time learning some new things from YouTube and reading other’s blogs. Below are some of the more interesting or less well known content I’ve found. Continue reading

MJE3055 Power Transistor Teardown

Whats inside a power transistor? Well some semiconductor to be a transistor of course. How large would you expect the transistor’s die to be?

My guess is, that for a device that can conduct up to 10 A, the die would occupy the bulk of the transistor’s package. What’s your guess?

MJE3055 NPN transistor
An MJE3055 NPN transistor ready to be dismembered.

Lets find out with a teardown of sorts with the following MJE3055 NPN power transistor that comes in a TO-220 package.

Continue reading