Archive | Fabrication

Brasilia Espresso Machine Restoration and PID Upgrade

I’ve been working on this project on and off for a few years. It started off as a simple restoration of a second hand Italian espresso machine which quickly got out of control, as most of my projects seem to do. Here’s a video showing the finished project and then a bunch of photos showing the build. I should have done the video with the camera turned the other way, sorry about that but I couldn’t be bothered re-doing it.

The Brasilia ‘Lady’ is a very simple single-group, single boiler machine. It has a 300ml brass boiler with a 3-way solenoid valve. It has a simple bimetallic thermostat which means the temperature swings wildly (although some models do have more complex thermostats). My model had no micro controller and was purely AC driven and controlled by the buttons on the front and the thermostat. The machine is in some ways very similar to the popular Silviamachine.

When I started restoring the machine I quickly decided that I wanted to do a PID modification to maintain a constant temperature. At the time I had just started playing around with Arduino so I thought why not just take all of the AC buttons on the front down to an Arduino and control everything through software with solid state relays for the pump, boiler and solenoid. The pictures and captions below should explain each part of the build sufficiently.

TLDR: Final assembly photos are at the bottom of the post.

Machine Housing

Case01

This is how the machine started out. This isn’t actually mine but I didn’t take a photo before I started. Mine was in much worse condition.

Very simplistic internals.

Very simplistic internals.

 

Case02

Case03

case04

There’s a lot you can do with a good set of files

Top Panel

TopPanel01

Template for top panel created in SketchUp

Template printed onto toner transfer paper

Template printed onto toner transfer paper

Thanks to Katt for the great idea of using PCB transfer paper for metal work.

TopPanel03

Template pressed onto 3.5MM aluminium plate with an old sandwich press

TopPanel04

TopPanel05

TopPanel06

Milling the display aperture and a recess so that the display is very close to the surface of the panel.

This Sieg SX3 mill is proving to be very useful. It’s the same as the Grizzly G0619

TopPanel07

TopPanel08

TopPanel09

TopPanel10

Polishing compounds in various grades

The polishing compounds came in a set of 12 syringes

TopPanel11

Shiny!

 

oLED Display Module

Display02

 

Display03

Display04

Display05

Display06

Display07

Display08

Display09


Display95

This 3M Double-sided tape is super strong.

Display10

Display11

The clear acrylic lens is sealed to the display module with 3M double sided tape.

 

Display12

Display13

 

PCB and Controller

PCB design created in KICAD. Such an awesome piece of software!

PCB design created in KICAD. Such an awesome piece of software!

Controller01

12 double layered PCBs delivered for $14 USD from DirtyPCBs.com. I’m not complaining!

Controller02

Controller03

Controller04

Controller05

Controller06

Controller07

 

Power Box

PowerBox01

 

Front LED

Led01

Led02

The led holder is made from stainless steel. A piece of fiber optic plastic is glued in as a lens.

 

Water Tank

Tank01

Tank02

Tank03

Tank04

Tank05

Tank06

Tank07

 

 

Water Inlet

WaterInlet01

WaterInlet02

WaterInlet03

WaterInlet04

WaterInlet05

WaterInlet06

 

I’m not sure why I made such an elaborate nut for this considering it’s hidden inside the machine. Never mind it was fun.

WaterInlet07

WaterInlet08

 

Final Assembly

Before the final assembly I had the machine casing stripped and powder coated in flame red.

Assembly01

Group head temperature probe

The group head temperature probe is held on with High temperature Kapton tape

Assembly02

Assembly03

Assembly04

Assembly05

The tube wrapped around the boiler is a pre-heat tube that I added so that the water being drawn into the boiler is not stone cold.

Assembly06

Assembly07

Assembly08

Assembly09

Assembly10

Assembly11

Assembly12

 

Assembly13

 

Final

Parts List: (Thanks China!)

  • Top plate: 3.5mm Aluminium (from HP Server blanking panels)
  • Display module: Cut from a block for 101 x 50mm Aluminium (New, local)
    • Display: Hide.HK I2C 1602 LED display. (via eBay ~20USD)
    • Display glass: Plexiglass 1.5mm (via ebay)
    • Display Tape: 3M 300LSE 9495LE Double Sided Adhesive  (sheets via AliExpress)
  • PCB printed by DirtyPCBs.com
    • Arduino Clone: Nano 3.0 clone (via AliExpress)
    • 2x Temperature sensor chip: MAX6675ISA SPI Interface (via AliExpress)
    • Connectors (via local JayCar Electronics)
  • PCB Box (via AliExpress)
  • Power Box – Aluminium (via local JayCar Electronics)
    • Solid-State relays (Can’t remember had bunch in a parts box for years)
    • DC power supply: From a Samsung USB charger
    • Rubber grommet kit (via AliExpress)
  • LED holder: From some stainless rod I had lying around
  • Water Take outlet: Stainless M10 Bolt
    • Silicon seal for water inlet – from a kit (via AliExpress)
  • Water inlet: 22mm Aluminum rod (New, local)
  • Silicon tube: 6x9mm food grade (via AliExpress)
  • Pre-Heat tube: 6.4mm (I think) copper (New, Local)

 

Thanks for stopping by. Feel free to ask questions.

Here is the source code and PCB schematic designs if anyone is interested. I’d be happy to have critique on either.

uCespresso PCB
Version:
Updated: 2015-07-21
Download: uCespresso PCB.zip - 334.13 kB
uCespresso Arduino Code
Version:
Updated: 2015-07-21
Download: uCespresso 0.75 Code.zip - 25.2 kB
25

First attempts at milling (and mobile blogging)

Here’s my first attempt at making something with the mill. Also my first attempt at using the WordPress mobile app to post. If this is easy maybe I’ll post more regularly. Micro-blogging I think they call it?

image

This just started out with milling into the body of an old HP harddrive to get a feel for the machine. Very high grade aluminium (I presume). Very easy to mill.

After a while this is what I came up with.

It’s an adjustable bracket. I think. For what? I’m not sure.

This is very exciting. The only limit is imagination…..I imagined an adjustable bracket. Oh that’s really sad!

0

First Lathe Projects

These are my first little lathe projects. After all, isn’t the point of having a lathe so that you can make improvements to your lathe?

These were made from bits of brass and steel I got from the scrap dealer. The threads were all cut with tap and die. The lathe can cut threads but I cannot (yet).

Thumb Screw for Gear Change Cover

I don’t yet have a knurling tool so I just put some rings around the outside for grip.

ChangeGreaKnob1

ChangeGreaKnob2

ChangeGreaKnob3

 

 

Replacement Handle for Carriage Wheel

This is to replace the plastic Carriage handle. Not that there is anything wrong with it. Just for the exercise really.

Carriage Wheel0

Carriage Wheel1

Carriage Wheel2

Carriage Wheel3

Carriage Wheel4

Carriage Wheel5

2

Resin Cast Project Enclosure

Project boxes available off the shelf always seem to be just too smahttps://blog.rhysgoodwin.com/wp-admin/post.php?post=973&action=edit&message=1ll or way too big!  This is especially true here in New Zealand where the options between JayCar and SurplusTronics are fairly limited.  I needed a specific size to house a project I’m working on so I decided to cast my own in Polyester Resin.  I hope the details which follow will prove helpful.

 

 

Draw up a design – I used Google Sketch up.  Make a box of which the inner dimensions represent the outer dimensions of your final enclosure.  I used blocks of pre-dressed pine.  You’ll want to use something reasonably solid and screw it down to a base board so you get nice square vertical sides.  For a base I used melamine board – it’s nice and smooth and the resin won’t bond to it.  Your local kitchen builder will give you off cuts for free if they’re nice.

 

Wrap the blocks with masking tape.  This provides three benefits:

  1. The waxy surface of the tape acts as a barrier between the wood the resin and makes de-molding easier
  2. It creates a nice flat surface to mold against
  3. Reduces the chance the resin leaking out because it forms a seal as the blocks are pressed together then screwed down

 

 

 

Put a mark on the side of at least one of the walls to indicate the height of the enclosure, this is where you will pour the resin up to.

Accuracy when cutting the wood is important if you want a professional looking result.  Decide on a tolerance and stick to it.  If you cut a length and it’s not within tolerance then re-do it.  If you don’t, you’re sure to be disappointed with the end result.  Resist the “She’ll be right” temptation – it won’t be right!  Errors are amplified at each stage of the process.  I worked to 0.5mm.  For me this was an excellent practice exercise in hand-saw and measuring accuracy.

 

Make a shape of which the outer dimensions will represent the inner dimensions of your finished enclosure.  This is where you decide on the thickness of the enclosure walls.  I made over-sized corners so that I had solid pillars to screw into.

 

Unless you’ve got a dead level work bench you’ll probably need to set up a little platform that you can level off with screws – like this:

 

 

Mix up some resin and pour it into the mold up to the height you marked.  Mix the resin and MEKP as per the instructions.  I mixed towards the higher end of the 1%-2% ratio, about 1.7%.  And please be careful with the MEKP.  Don’t even think of going near it without eye protection and gloves.  MEKP is a severe skin irritant and can cause progressive corrosive damage or blindness.

 

 

Now the fun bit.  After a few hours the resin will be hard enough to remove it from the mold.  Unscrew and remove the inner blocks and as many outer blocks as you need to get the enclosure out.

It will be a bit hard to get out because the resin shrinks a little bit as it cures.  It will probably also still be a bit sticky when it comes out.

 

 

Now on to the top and bottom sections.  You could just cut some flat plexi-glass for this but while we’re at it we might as well just cast them.  Clean up the enclosure with sand paper.  I used wet/dry from 120 grit up to 400.

Drill and tap the corners.

 

 

Use making tape to mask off the areas where the resin will touch.  Screw in 4 countersunk lid screws leaving them out to the height you want the thickness of top lid to be (I made mine 4mm).  Make sure they are all exactly the same height.

 

 

Reassemble the outer box of the mold on a new piece of melamine and place the enclosure back in, screws down.  The enclosure will have shrunk since it was last in the mold so use multiple layers of masking tape as packers to center it (use an even number of layers on each opposing side).

 

Make sure your platform is dead level and pour the resin into the mold so it just comes up over the sides of the enclosure.  This will make a locking lip on the lid.

 

After a few hours you can de-mold the box with lid attached.  It will be stuck to the board but just slowly ease it away, you almost have to peel it up. Don’t try to knock or tap it.  With a bit of luck you’ll be able to remove the screws from lid and take the lid off without too much difficulty.  Making the lid this way takes care of the screw holes and countersinking.

 

Now repeat the process for bottom lid.  For the bottom I didn’t mask it off because I wanted it sealed on – I don’t need to remove it.  I also made it a bit thicker so it’s nice and solid for mounting to.

 

Once you’re all done you can sand/polish the enclosure as much or as little as you like.  I left it with a frosted look but you could shine it up to be completely transparent if you wanted.  I also removed the thread from the holes in the lid.

 

 

 

Well that’s quite a process! But the result is good and it’s good practice for accuracy, woodwork and resin casting.  I tried a number of methods before I came up this and it’s by no means perfected – as always I’m keen to hear your ideas.

40