Monday, 1 September 2008

Universal Pen Holder and Touch Probe Tool Head

I have designed, built and documented a Universal Pen Holder and Touch Probe Tool Head I wanted a way to put etch/photo resist directly onto PCB's, pen plot, photo plot, digitize items I had made ready for RP'ing and most importantly an easy way to setup and check mechanical alignments on my Darwin PlyRap Machine

Follow the link above to view the documentation.

Wednesday, 13 August 2008

PlyRap Build so far

It's not been all hard work, above is the progress so far on building a ply wood Darwin RepRap aka PlyRap. This is a near duplicate of the one built by Toby Borland and exhibited at the Science Museum in Kensington London.

The RepRap Project can be found here.

Together with the build instructions I have been documenting as I go along.

Duck Housing

Here's the ducks and below is the house and pen I made for them to while away their hours in when not eating and swimming on the pond.

I think in my next life I want to be a duck. How much bad karma do I have to rack up to be demoted to duck status ????

Flower Bed

A raised flower bed, it's amazing what you can do with a chain saw and a couple of old railway sleepers.


Progress here on the electronic/robotics work has been a touch slow as there has been so much other stuff to be done whilst the weather is suitable for outdoor work. Autumn and eventually winter will put paid to that and the fun stuff can resume.

Just to catch up here's some of the other things produced in the Kitchen Workshop starting with a pair of composters (Adjustable height).

Wednesday, 23 April 2008

Xillinx Controler Board Design Underway

My controller board design or at least the FPGA programmable logic part is nearing completion and work on schematic capture is underway. Hopefully this will be followed by PCB layout and prototype.

The FPGA board will be a separate plug on board that will piggy back onto the board/s that hold the interfacing and power driving sections of the design.

Doing it this way makes it possible to use the board in other designs without a full redesign. I guess it makes a good Programmable Logic experimenter board too.

The Design uses the Xillinx Spartan 3E and can be programmed and debugged using the JTAG interface. (Socket provided on logic board)

Progress is a touch slow at the moment as I am catching up on a list of stuff that needs doing around the place now the weather is picking up.

Friday, 21 March 2008

All the bits put together

Finally the fully completed article all put together.

This will be the last post covering construction of the Ball Mill other than if it sneaks into shot as I work on other things.

Making Milling Containers

The Milling container made out of 4" (110mm) Pipe and End Caps. Again I purchased these from Hunts Pipeline Supplies in Normanton, West Yorkshire they are really helpful and can supply pipe cut to length.

The pipe and the end caps are very robust and should with stand using larger and heavier balls if I need to.

One of the End Caps is glued on using a solvent adhesive and the other just slides on.

These are just fine for powders but if I need to mix/grind using liquids of some variety or other I will need to use a liquid tight inner container.

Saturday, 15 March 2008

Milling with Balls and a Kitchenaid

OK here is the completed ball mill, all the separate parts put together and milling.

In the container on the mill are 50 10mm steel ball bearings and the lumps of anhydrous magnesium sulphate that need to be ground to a fine-ish powder.

The elastic bands round the container are to reduce slippage and help the drive roller with traction.

I will complete the milling during the week when the noise won't disrupt as many people, it being the weekend and all.

Fitting the Adapter to the Mixer

Here is the adapter inserted into the Kitchenaid food mixer's PTO.

All ready to go.

PTO Adapter Assembled

Here is the assembled Kitchenaid PTO adapter with the flexible coupling attached.

Note the bearing retaining pin inserted and bent over to stop it dropping back out.

Kitchenaid PTO Components complete

The components for the Kitchenaid PTO adapter complete and laid out.

The turned and filed 12mm Aluminum Bar, turned down to 8mm (Bearing race inner diameter and inner diameter of the flexible coupling) and drilled to take a wire pin. The pin is to stop the bearing from moving down the shaft during use.

Note the piece of copper wire to use as the bearing retaining pin and the Skate bearing.

The purpose of the bearing is to keep the PTO shaft roughly aligned with the center of the housing even when the alignment is displaced. I guess it stops things catching and rubbing.

Thursday, 13 March 2008

Finalised Xilinx Development Environment

Having spent the last 4 or 5 days messing with setting up a build environment for the up coming Servo Controller design work I have finally got a method that seems to do what I want even though it appears to have a few installation glitches.

Most of my development environments are stand alone machines set up as Virtual Machines On a Ubuntu Workstation running VMware-Server. This makes it easier to backup/restore and ensures that one set of build tools and their upgrades has no effect on another.

The final model that seems to work (at least until I try and use it in anger) is Ubuntu Feisty (7.04) with the down loadable Xilinx netpack 9.2i installed as the development environment.

I needed to get the single file complete down load from xilinx even though it is huge. Installation proceeds relatively painlessly initially but does not give you the opportunity to enter a product code. As the installation progresses there appear to be 5 zip archive which won't uncompress these fail with errors and when complete xilinx's update utility fails part way through too.

When you run up the software though it looks to be a runner.

We'll just have to wait and see.

Turning a PTO on a Drill Press

The Ball Mill frame is now glued and screwed together and awaiting some milling. Last bit to make is the PTO (Power Take Off) adapter.

Our food mixer has a PTO on the end of the body that is used to plug other accessories into. This PTO is recessed and is simply a 12mm square key in the end of a rotating shaft.

I have some 12mm square aluminum bar and have cut out a section to make the adapter from.

The rubber hose of the flexible coupling already made for the purpose though needs to be fitted to a round 8mm shaft.

Here's a picture of the drill press being used as a rough lathe.

Basically the Aluminum bar to be turned down is clamped in the Drill Chuck and left hand offset lathe tool is clamped in the Drill Press Vice. If it is all carefully aligned then the piece can be turned in stages by running the drill and pressing the rotating Aluminum bar towards the Lathe Tool.

It is problematic to take too much material of at a go as the arrangement is a touch prone to vibration which messes up the alignment.

The results are a touch rough but look to be serviceable. Lubricating the workpiece with 3 in 1 oil at regular intervals seems to improve the cutting speed and reduces vibration.

Hopefully this will get finished over the weekend.

Monday, 10 March 2008

Ball Mill Frame Ready for Screwing

The Ball Mill Frame put together with the rollers (They just slot easily in to the bearings inner races) and ready for Gluing and Screwing.

Note the end of the drive roller sticking through the end block. This is where I will be attaching the flexible drive coupling we made earlier.

The rollers are spaced 90mm apart in anticipation of using inexpensive 110mm plastic soil pipe and fittings to make up milling containers.

The end support blocks which also act as spacers for the frame sides are 140mm long to ensure that we get adequate clearance for the 110mm pipe and fittings.

Frame and Rollers Laid Out

The Rollers and Frame components laid out. Note the bearings have been pressed into the end support blocks.

I used a socket from my socket set (with the same Outer Diameter as the outer race of the bearings) as a drift and a vice as a press to push the bearings into the 22mm holes in the wood blocks. It is quite a tight fit.

Take care no to push them too far in as the inner race will foul the bottom of the hole. (The 22mm Holes don't go all the way through)

After drilling the 22mm holes with the hole saw I drilled 10mm holes right through each 22mm Hole center to ensure that the 8mm drive shafts do not catch on the wood.

Drill Press Setup

Here's my repaired drill press set up ready to drill the holes in the end support blocks for the bearings.

Note the line drawn around the end of the 22mm hole saw to gauge the depth of the hole and make all four the same.

22mm is just the right size for the outer race on Skate Bearings, it makes the fitting tight enough to hold the bearing in place without needing any other form of fixing.

Monday, 3 March 2008

Rollers and Coupling Complete

Here's the end detail on the Idler and Drive Rollers showing the bearings slipped on to the ends.

Here's the Idler Roller, Drive Roller and Flexible Coupling complete.

The Idling Roller Assembled

Here is the Idler Roller construction finished. Note the Skate Bearings slipped on to the ends of the roller. These will be held in place by the mounting blocks I have yet to make.

Sticking the Rubber to the Rod

Here I started to assemble the rollers. As the 8mm tube was a loose fit I smeared a quarter of the rod with Evo Stick. I did this half the way down so that as the Rubber tube is slipped onto the rod (Using a twisting action) all of the Evo Stick is smeared inside the tube with non left to clean up by the time the rubber tube has made it to the end washer.

The Evo Stick helped slide the rubber onto the rod but when it has set will stop the rubber from turning on the rod.

Does all of this sound dodgy or do I need to get out more.

Ball Mill Roller Parts

OK Here are all the parts for the Ball Mill rollers laid out:-

2 pieces of rubber tube 8mm inside diameter at 300mm
1 piece M8 threaded rod 333mm long
1 Piece M8 threaded rod 336mm long
4 608 Abec 7 Skate Bearings
4 Nyloc M8 nuts
4 M8 Washers
1 short piece of rubber tube 8mm inside diameter to use as a flexible coupling
2 Jubilee hose clips to attache the flexible coupling

Umm the red stuff in the background is my kitchen table. It is after all kitchen table technology.

Rubber Tube for Ball Mill Rollers arives

The Rubber tube I had ordered from Machine Mart arrived today. This is to make the sticky part of the rollers for my Ball Mill. I ordered two sorts because I wasn't sure which would work best.

Their Gas Test tube is the right diameter for a tight fit on M6 Threaded Rod.

Their 8mm Air Line tube is a loose fit on M8 Threaded Rod. Unfortunately the smallest quantity of this I could Get was 10M but i have a feeling I will be using the surplus elsewhere.

The Air Line tube arrived with crimp fitted unions on each end. As it was a shame to waste them I cut them off with 60cm tails so that I could later add PCL hose fittings to them and use them as Air Tool quick release tails.

Thursday, 28 February 2008

Aborted attempt to make Rubber Rollers

I tried to make some rubber rollers for the Ball Mill yesterday.

In lieu if having any rubber pipe with an inside diameter of 8mm kicking about I tried molding rubber rollers using some Vinamold compound I had to hand and a piece of copper pipe.

All in all a dismal failure, the Vinamold as well as being Smelly/Smokey to work with when it is melted it is pretty viscose.

It couldn't flow down the copper pipe quickly enough as it cooled and the result was stuck all round the inside of the pipe and full of voids.

The roller core pulled out too easily as well (I had used a thin aluminum tube with OD of 8mm to fit the bearings and an ID of 6mm to fasten the roller to the bearings using M6 Studding and Nyloc Nuts.

Having tried this as an experiment, I think it could be successful if a two part mold was used instead of a tube. The mold is better made out of something that is a poorer conductor of heat too, so that the Vinamold doesn't set too quick.

I think I need to return to plan A and find some rubber pipe/hose that suits the job, for now.

Making a two part mold I think is a task for the milling machine when it is complete.

Don't Ball Mill in a Glass Vessel.

Progress is slow here at the moment.

Quick tip don't try ball milling in a glass vessel no matter how robust it feels, the glass will give. Even when done gently by hand.

I tried this to get the Anhydrous MgSO4 out of the Duran Bottle I had dried it in. Unfortunately it had caked around the sides.

Net result was that the bottle slowly went crazy paving. Upside though was I did get the lumps out of the bottle and transfered to another container one way or another, just wasted the bottle.

Wednesday, 27 February 2008

Orders mostly arrived

OK The steel has arrived, it took a while to hacksaw into halves for storage but is now done.

Have got a 34mm hole saw and the Ball bearings have arrived, hopefully we'll have some more progress soon and some more piccys to put up.

Monday, 25 February 2008

Ordered up Steel for next part of construction

Ordered up some 30mm x 30mm x 3mm square tube and the same in equal angle.

The square is to make the rails for the axes, I just need to locate a 34mm bi-metal hole saw now to fish mouth the ends of the square tube to fit the round profile of the frame tubes.

The angle will be used with the bearing units already constructed to make the carriages or running bits for the axes.

I think I will be drilling the frame pipes and putting M8 threaded stud through to clamp the rails in place. I have discounted welding as the frame is galvanized.

Now the drill is fixed I can do these things.

Thursday, 21 February 2008

Finished Anhydrous Conversion

Finished off the oven work for converting the MgSO4.7H20 to MgSO4, or at least I think I did. My kitchen scales are so vague I could be slightly out.

Best that I can tell it all worked though.

Also went to the supplier to get some Steel Ball Bearings to pulverise the MgSO4 into fine powder but they were out of stock. Ordered them anyway and will await their arrival.

Next task in the interim is to figure out how to make myself a Ball Mill. As I have no useful motors lying around I think I will try and sneak some time in, using the Food mixer's Power take off to drive the Mill.

Just need to make the rest of the Mill now.

Pillar Drill Fixed

The pillar drill is now fixed and operational again.

Yipee, basic machine tool now back on line. It is amazing just how much you take certain simple things for granted until they are no longer there.

So much frustration is caused by those moments when you think I could just do this , then that then the other...... ah I couldn't do just this because I have no pillar drill.


Wednesday, 20 February 2008

Started search to find a support paste

Started initial experimentation to find a salt based support paste for use in the second head of the Ianus Rapid Prototyping Machine.

First up is an attempt to use Epsom Salts (Magnesium Sulphate, MgSO4) starting with reducing the commonly available form into a fine ground anhydrous version.

Baking in the oven at 210 Deg Centigrade seems to be working but had to halt the experiment so we could make the evening meal in th oven. Will resume tomorrow.

Parts Arrived To Fix Pillar Drill

The parts arrived today to fix the pillar drill, so we had a session in the workshop and stripped the broken pieces from the drill. Ready to refit the new pieces tomorrow.

They must have had problems with the originals because the replacements have thicker castings and a metal crank instead of the plastic one.

Tuesday, 19 February 2008

Blagged the use of a Lathe

I have blagged the use of a Lathe from a good friend but need to repair it first, this is going to come in useful for those, if only I could turn this down/out by an x jobs. But I will need to organize myself to work on this as it is a 40Min 33Mile journey away. I guess this means no nipping back to try the part on Ianus

Monday, 18 February 2008

Pillar Drill Fixing Underway

Ordered the spare parts I wanted for my pillar drill over the weekend, hopping from foot to foot now waiting for them.

The table support casting had shattered where it tightens around the post one cold morning (Must be heat and cold combined with a weak casting).

The table had come crashing down the post and bent the carriage and trashed a couple of other essential bits on the way down.

Thursday, 14 February 2008

Ianus Bearing Mounts

Now I can start on work towards the slides etc for Ianus, here is the assembled bearing mounts ready to mount on trolleys. The idea for these came from clever but simple, the best ideas always are. We are using Skate bearings (608 ABEC 7) here, M8 x 20mm Machine Screws and M8 Nuts. These screw right into drilled and tapped holes on the trolleys.

Ianus Frame Assembly.

Ianus frame assembled and screwed down to base board gantry not tightened up to base frame yet as it needs positioning etc.

Ianus Initial Assembly

Ianus initial assembly, Note working lunch on table.

Ianus is born

Ianus is born (well the prototype test bed is at least)

Ianus is a dual head Cartesian with Independent Z axes on a common X and common Y platform.

The Y axis is the worktable which is full width and slides backwards and forwards on the bed frame.

The X axis is mounted to the head of the gantry and slides full width.

The independent Z axes are mounted to the X axis on the gantry one per side initially, though this could be modified to present more independent Z axes ie 4.

The tubes and fittings I wanted have arrived and I have assembled them to trial the ideas. I bought the pipe and clamps from they are located in Normanton, West Yorkshire, UK