Ok we are back in business!

Money shortages are finally under control and things are looking good for the next few months.

I've been in contact with another westcountry engineer who has very kindly spent some time sourcing some basic but essential parts for me, in particualr a pair of proper heavy duty engineers machine vices and a few other pieces of workholding equipment.

With the winter weather drawing in, daylight up at the barn has become very limited so I figured it was time to sort out some proper lighting. Until now I've been making do with daylight and using builders halogens for the occasional bit of detail work but theyre horribly innefficent and tend to blind you rather than provide a useful level of light. Was looking at suitable florecent alternatives and managed to blag a pair of nearly new metal halide factory lights with blulbs on ebay for a quid! An elegant and cheap solution - just got to work out a way to get them on the celing now - theyre not exactly light or easy to hold whilst precariously balanced on a ladder. Also got permission to put a wood burner in the barn so once it gets cold that'll be the heating sorted.

The mill, having not been used for a couple of months now has suffered a bit from damp. Mechanically everything is fine from a surplus of oil however the contacts on one of the time delay relays in the servo PSU have become a bit sticky so that might be due for replacement soon if a bit of regular useage doesnt fix it. The plan now is to carry on where I left off, get the encoder covered machined up, finish off the other loose ends and finally complete the project. Then for stage 2, make some money! This thing has been draining my wallet for too long and its high time that it pays its own way. At the very least I want to make back what I put into it; hopefully a lot more.

In addition to lights and heating I want to improve the conditions in the barn a bit. At the moment it is a bit exposed with an open front so I'm going to partition off the back half with a wall of tarp and then eventually build a solid wall in its place. Initially I built an electricity meter into the electrical cabinet of the mill itself thinking that would be a sensible way to monitor and pay for electricity useage, however thinking about it now theres going to be a lot of other things, lights, computers etc which will all need power and wont be counted so I'm going to take the meter out of the mill cabinet and mount it on its own box along with a small consumer unit. Then I can run a chunky feed from the main fuse box, via my own digital meter and then everything will connect after that. Possibly a little overkill atm but soon it will be a necessity.

Still not sure what to do about the software side of things. I have a lot to learn for a start. Think it will be just a case of experimenting with a lot of demos and finding out through trial and error what would be a good solution. I'm also hoping to do some work experience at a friend's local engineering firm to get some hands on experience with cnc stuff seeing how it's done for real. So far they've been too busy to fit me in but sooner or later hopefully we'll be able to sort something out. I'm sure it will be an eye opener.

I need to start posting on here more regularly. Just realised today how valuable this resource is as an aide memoire to stuff I've done a while back and since forgotten about.

I've been taking time to learn a variety of CAM packages and trying to get my head around 3D toolpaths, offsets and coordinate systems. Its a very steep learning curve but i've found some good resources on the internet. For simple 2d stuff i'm still liking cambam as my prefered program however I recently came accross a website offering in depth mastercam training videos and a free download of the home learning edition of matercam which lets you do everything except for posting gcode so its ideal for messing about with and i'm loving the toolpath verification stuff. I still have a hell of a lot to learn tho as its not exactly what you could call intuitive.

The website in question is http://www.eapprentice.net/ which also has a great support forum. Prices for access to the video library is very reasonable too at around £15 a month.

So today I went up to the barn with the intention of machining out the long awaited encoder housings and having now obtained the materials and a fantastic big machine vice I thought I was all ready to rock. Unforuntatly an old problem raised its ugly head and my Y axis drive kept tripping out leaving me unable to machine a single part. I'm at a bit of a loss as to whats going on having exausted all my own suggestions so i've sent an email over to Tom at Rutex and eagarly await his response.

I thought you had been busy the last few months making chips..

I wish.

Sooo, latest progress is as follows. Still not 100% certain on the cause of this new fault but all the clues are pointing towards a lack of supply power. It was something i had considered ages ago as a possible cause of another problem but then those problems went away by doing other things so I had not considered it since.

At first the ovbious things seemed to be faulty encoders, wiring, servo drives, etc but after systematically testing everything and crossing these things off one, everything is pointing to a poor power suppy as being the most likley cause; on the basis that everything works on its own & its only when everything is run together and high speeds/accelerations when the problems seem to start.

It is possible that it is asking too much of a 50m 13amp extension cable to drive a 3 ton bridgeport and that whilst previously it was just about ok, adding a 60kg machine vice to the table was enough to push it over the edge. I always assumed that when I pushed the cable too hard i'd start blowing fuses first, but if the voltage drop is causing a positioning error then perhaps the machine is faulting out before it can run long enough to blow the fuse in the plug.

The next plan is to borrow a large generator to test the theory, and if everything works fine then it'll be time to run some 10mm cable from the main fuse box and wire in the machine properly. I'm really hoping a lack of power is the problem now as it will be by far the cheapest and simplest thing to solve and will mean i'm actually quite close to finishing the machine.

Once that problem is out of the way I really hope I can start to tie up the loose ends and start producing some value from this beast of a machine.

Remaining to do list off the top of my head is as follows:

#Reconnect Charge pump

#Add wire to stop machine entire machine if any one of the drives fail

#Wire in drawbar position sensor

#Build new encoder housings

# Wire in spindle rev sensor

# Clean/Remove rust from right hand side x-axis ballscrew cover and refit to machine

with that done, barring any more major problems that will be the machine finished enough to start cutting some parts and potentially making a bit of money.

Then for the finishing touches:

# Replace y axis flexible covers with new

# Repaint areas where the finish has eroded

# Refit all the fibreglass panels

# Rewire controls above the quill via a pokeys board so z axis can be jogged and zeroed more easily

and Finally:

# Build an MPG Handwheel control

# Build a free standing control unit to house a touch screen interface to mach along with any additional buttons and switches

# Go through existing doccumentation, update everything and produce complete doccumentation package so the machine can be maintained easily in future long after i've forgotten where everything goes. This will include software backups and parameter print outs for both mach and servodrive firmware etc.


Possible future improvents not essential but may be useful at some point:

# Build a steel box section + polycarbonate enclosure around the entire machine to make it more like a vmc so all mess and potential projectiles are shielded from the operator

# replace internal 5v/12v psu with something a little beefier

# Rotary table 4th axis?


My intention is to get all the important stuff done within the next couple of months which is going to require some careful planning to ensure I have a suitable budget to support it. In addition to the machine itself I'm slowly making improvements to the building in which it is kept, making it better suited for my requirements.

It seems that hiring a generator is going to cost as much as buying a 50 metre reel of 10mm cable so I'm just going to go on the assumption that a lack of power is causing my problems and bite the bullet so to speak. Spoke to two electricians who are going to quote me for the work, my intention of course is to do 99% of the work myself and just pay for someone to hook it up to the consumer unit.

Today (well technically yesterday as its now past midnight) I wired up a new DB15 connector for the rutex motherboard which included an extra output wire for hooking up to the charge pump and also a few link wires, one of which allows the drive to be accessed via the motor tuning software - this means I lose an output pin but saves having to plug in a special cable whenever i want to access the servodrive firmware. The other link sends a signal from the drives to the pc if any of the drives trips due to over current or following error etc. This is a very important feature as without it if one drive stops working the rest will carry on as if nothing has happened with potentially disasterous consequences. In order to make this work however It's going to require a bit of vb script which i'll have to look into tomorrow.

Today I also ordered a 5v voltage reg so I can wire in the drawbar prox sensor and include it in the code for the tool release button. Was going to order from rapid electronics but £5.50 postage for a single voltage reg costing 90p and weighing a few grams seemd somewhat excessive; they refused to negotiate on that price so I took my business elsewhere. Went to ebay and bought a pack of 5 voltage regs for 99p and paid 80p for postage (next day delivery too apparently - rapid could learn a few things from this seller!)

Still waiting for my new encoder discs to arrive. Cant belive I had to pay by cheque - would have been quicker and easier to order direct from US digital in the US rather than their rather technologically backward uk distributor.

Yesterday was a disaster. Went up to the workshop with high hopes of progress with new cable in hand however it was not to be and everything went tits up. New cable didnt work (seems you cant leave the link in for programing the drives whilst in step/dir mode), removed the link & the drives came back on but the wire for the charge pump didnt work. Then the monitor for the pc pretty much exploded (screen went black followed by very loud sounds of electrical arcing). Big shout out to http://www.compwork.co.uk/ who kindly donated a new 17" crt to my cause though by then it was getting late and didnt really achieve much else that day.

Today I actually made some progress. Got up to to workshop earlyish and first took the fuses out the big power supply and shut off the breaker for the spindle motor, My plan was to focus on the logic circuits today and by doing that it meant I could power down the machine and work on it instantly without having to wait 5 mins for the big scary capacitors to discarge.

On the basis the connection from the rutex db15 connector wasnt goiing to work i set about connecting the charge pump up to the lpt2 breakout board. This would definatly work but because this board has a power supply which is disabled by the charge pump it woudld be necessary to add a physical enable switch to bypass the charge pump just long enough to power up the break out board which would then supply a 12.5khz signal to the chargepump keeping it locked on until mach should fail or the computer is powered off.

I figured the best place to put this switch would be at the top of the machine beside the stop switch and various other buttons. Looking behind the panel i realised there were no wires running up there and trying to push new ones through the conduit was proving difficult. Thinking ahead, i made up a 9 wire loom to cater for any potential future switches or lights and with a bit of perswasion managed to run it between the top of the head and the electrical cabinet.

It was only when looking for the right place to wire in the switch I realised the charge pump itself was missing a power feed and that this was the most likley cause for the output from the rutex motherboard not working previously. I wired it back to pin 10 on lpt1 and set that pin as the a axis limit in mach and gave it a try. It worked, but the wong way round so had to go back to the settings and tick the active low box. Second try was a step in the right direction but still not quite there. Turned on machine with mach in estop mode, machine stayed powered down. Reset the estop condition, machine powered up for half a second and then shut off. It was then I discovered a little known flaw in the rutex system whereby the output pins briefly change state (from high to low.. or vice versa) when powered up. This meant as soon as the drive powered up, it was self tirggering an estop through the charge pump. I thought of a number of ways to get around this but ended up picking the simplest option of ticking a box in mach general config which means the charge pump remains on in estop mode. This is probably a good thing else it would end up shutting down the entire machine whille the drives were disabled during a tool change for example. Besides, the main reason for the charge pump is to prevent the machine doing strange things when mach is NOT in control of it. In estop mode mach is still very much incontrol and nothing odd should happen. It's worth bearing in mind that this is purely a software safety system, the real estop (as in the big red button on the front of the machine) works independant of software and will power everything down regardless of what the computer wants to do.

I then went onto solving the problem of the machine carrying on running a program when a drive had failed and tripped out for whatever reason. Last time could not get this feature to work and pondered over every possible thing, except of course the most ovbious. I had a vague reccolection of a setting in the motor tuning software and sure enough when i loaded it up there was a checkbox to enable the ouput of a signal when a fault was registered. Ticked 3 boxes, updated the firmware and all of a sudden things started working. Set it up as a A axis limit switch to port 1 pin 10 and then ran a program which i knew would cause a following error. This time it worked as expected and triggered a software e-stop condition. This was another good reason for not having the charge pump turn things off when in estop mode - If a drive faults out with the other two running, I want to stop them by discontinuing the software commands to move, not just by removing the logic power supply from the boards while they are still moving at full pelt!

I then moved into wiring in the last few sensors which havent yet been done - the oil levle sensor, the drawbar height sensor and the spindle rotation sensor. It was at this point I realised i had run out of inputs and would have to look for another alterntative.

Thought about hacking a keyboard and hardwiring the F keys to switches and sensor outputs as it would be a nice cheap solution. Then I discovered they pokeys 55 device, a usb interface with about 50 I/O connections including analouge as well and a mach3 plugin. At just £50 from a uk supplier that was my mind made up and i ordered one this morning. With so many inputs and outputs it'll cover all future upgrades both planned and unplanned. Things like the handwheel pendant will just be a case of screwing in a few wires and configuring the software. All I need to do now is get my head around the vb scripting and write a few macros so mach can respond in a useful way to the sensor data.

Discovered the prox sensor on the drawbar seems to have died. New ones on ebay are around the £20 mark. Not a big deal then but a bit strange it should stop working when it hasnt even been used.

Pokeys board arrived today, its much smaller than I thought it would be but looks awesome. i will get it set up on my home compuer and have a play over the next few days - no point freezing to death in a barn when i can develop all the software at home in comfort!

Encoder wheels have finally arrived. Maybe 4 - 6 weeks after ordering. Never again will I order from the only UK supplier of usdigital parts. could have ordered them from the US in 3 days!!!

Need to save some money to put in the 10mm2 cable between the main consumer unit and my barn. If I go for armoured its gonna cost £150 just for the cable and then probs at least another 50 on top for plugs, sockets, second consumer unit, cable clips etc. Hoping that now I have the fault detection set up properly I can cut out parts running the machine at reduced acceleration and then if it does cut out from lack of power it will stop instead of destroying the part and tool.

Been proper busy at work in the restaurant what with it being easter holidays; that combined with a bit of essential car maintainence has reduced my spare time for playing with cnc stuff.

I had a play with the pokeys board tonight, plugged in an LED and a switch. Managed to map the switch to an ascii character very easily however couldnt get the output function to work properly. Clearly going to have to do some reading up on the subject .

Made some more progress with the pokeys board today. Worked out that to use it in mach you must first configure it with it's own software to specify which pins are outputs and which are inputs. Then in mach chosing port 10 and a pin number in the ports/pins config will give you access to the I/O. Often it will be necessary to tick the active low box.

I now need to get my head around macro programming in mach 3 so I can assign some logic to my inputs and outputs.

Discovered brains in mach 3, a kind of diagramatic logic programming environment. I'm not sure what to make of it yet. It seems like something that could be very powerful if it was made to work like the siemens logosoft plc programming software however as it stands its very over simpliefied which makes it difficult to do anything but the simplest of tasks. And as ever with mach3 doccumentation is few and far between. On the plus did I did manage to make a brain to deal with the servo drives faulting so now if one trips, mach knows about it and stops everything in an instant.

Armed with knew knowledge and a new part to try and machine I went up to the workshop in high spirits. Everything started off well, got the servo trip brain installed and tweaked the cam for the part I wanted to machine. Did an air cut and all seemed well then all of a sudden the charge pump started to malfunction and was pulsing rapidly on an off regardless of what mach3 was doing. I think the board could be faulty/dying and I know there is a newer version which is supposed to be much improved so I think its time for an upgrade.

I removed the charge pump and went back to my part. tried a second air cut - no problems. Went to cut it out for real and it had cut no more than 5mm before the slot drill snapped. That was the only one I had so decided to call it a day. Got some more ordered for tomorrow lunch time, going to have to be a bit more careful with my feeds and speeds and workholding. cant afford to snap too often!

Never Say Never!

Thought the day might never come but last week I actually managed to machine some steel parts for the first time ever. I made 5 identical pieces and the machine performed faultlessly throughout. The only hickup was on the last one when the pc crashed when I shut down another pc that was networked to it. Might have to put a network switch inbetween to prevent that from happening again.

The machine was of course still running at very reduced acceleration rates as i've not yet been able to improve the mains power supply to the building, that will come in due course. I've recently disovered there is actually a phone line up at the barn so the next priority is to get broadband installed as at the moment a lot more time is spent on research than actual milling. And of course then I can hook up a VOIP phone and all sorts.

Progress:






As far as the machine itself goes, next priority is to finally machine up those encoder covers now I know it can run reliably and make a few mods/additions to the machine itself, a new control panel up on the head with jogging buttons and a proper button for the drawbar release.

Good to see you have chopped some metal.
I wasn't going to network the pc on mine, I wanted to have it running with
as few services as possible. I can imagine windows phoning home to bill when you
cutting something worth a lot with a very expensive cutter.

What did you do, if anything, about inrush current when you switch the power supply on?

Hi Graffian. Nice to see I have at least one person still reading this blog! I was going to avoid networking in the first place for the same reasons you state however i've seen so many big expensive modern pc based machines in industry that all have LAN and often WLAN as standard I thought I might as well join the trend!

The powersupply for the servos is split into separate 4 x 1kw units. The 4th is currently unused (spare in case i want a 4th axis). I've got each pair of 1kw modules on a 16A Finder time delay relay. I set the first relay to energise after about 20 seconds which allows the VFD to power up along with everything else. Then a few seconds later the second pair of 1kw modules power up. I've also used fuses inside the machine which are designed to cope with the high inrush current though the single 13amp fuse in the extension cord that is running everything still hasnt popped so its ovbiously not a massive problem. I think if i tried to switch on all 4 x 1kw supplies on at once it may be a different story.


Todays progress: Dug out the 10mm ali plate which will be used to machine the base of the new encoder covers. Armed with new knowledge from recent experimentation I started tweaking the toolpaths as well.

Made some more progress with the cad/cam stuff for the encoder covers. Trying to optimise the toolpaths as much as possible to save cutting time and reduce chances of broken cutters and suchlike. Going to be cutting some of these bits from 20mm ali plate so its going to get expensive if i dont get it right first time!

Prototyped the encoder cover base into a bit of ply today and got promising results. I just need to try once more from a harder material like ali or plastic so I can hold it up against the part it's meant to mate with and ensure i've actually drawn all the holes in the right places.

Completed milling the plywood prototype of the encoder cover base, looks about right but will measure everything properly on monday. Ordered broadband for the workshop today, should make research and communication much easier. New consumer unit arrived: 1 x 60a RCD, 100 amp isolator and a whole load of MCB's. I'll get that mounted on the wall next week ready for the armoured power cable. Also arrived today, a 50m reel of exterior telecoms cable to extend the phone line. Still waiting on sockets and cable clips etc.

Remaining telecoms stuff arrived. Plan is to install that tomorrow evening. Today machined out another prototype of the encoder cover base; this time from 3mm ali. Overall went well, though did learn the importance of double checking CAM files before generating code. One the final cut out it was meant to do 2mm per pass but was actually set to 4mm. It made some nasty noises but I managed to pause it before any damage was done.

Had another play, this time tried to make a vehicle badge for my mate's landrover business. Didnt come out perfect and took forever to machine but wasnt bad for a first attempt and learnt a lot from it.