Second Fin Jig Finished
 

This evening I made the second part of the fin jig system.
A video for you all to watch - http://www.youtube.com/watch?v=v0KWimmYCzY

The end product - the photo does not show much detail I'm afraid but the video shows what is going on quite clearly.
Attachment 11438

Regards
Ross

Ross, if you are going to do a lot of text carving, you will want a better programmer to create the G-code and speed up the letter cutting drastically. 10 years ago we used VCarvZ (probably obsolete now) and it was a lot more efficient than what you have at the start of the video.

Aspire does that to have sharp corners on letters, it can be turned off and speed up the process.

Thanks Gerald and Danilo

Gerald I followed up the VCarvZ application and it is mentioned on the shopbot forum around the time you mention, however the trail has gone cold and the site is down now.
I'm sure the code will live on somewhere re-badged or merged into another vendors product.
I appreciate that you can just look at something and suggest an improvement.

Generally I have been going at things with very reserved feed rates like 15mm per second and also the motor acceleration smoothed quite a bit (something like .2 -.3 G).
Might have to wind the wick up a bit.

PS - you could also grow a beard (or improve your existing) waiting for the slow plunge rate I used for the cutter to hit the work piece.

Regards
Ross

Regards
Ross

Ross, if you are using Vector for the text carving, I am sure they will be the first to admit that your video is nearly like watching paint dry. It is probably just a case of settings in Vector. Yeah, most of the problem is the surplus Z-moves in terms of quantity, distance and speed. Cutting the curves of the letter seems fairly okay....most of the text carving programs seem to want to go twice on each part of the letter.

Mdf
 

Just a short post to say how much I dislike MDF.

This afternoon I recut one of my fin jigs, this time at least 4x the speed and it was done in a flash.
I have connected my old but now refurbished 1700 CFM dust extractor up to the dust foot and it clears the fine dust away nicely.
After a job is run their is no visible dust in the air but I'm not fooling myself I know it is still there.

Thing is, the MDF dust is still in the cut grove and after a few stokes with the sandpaper on the edges and it is still all over you even for a small job.
It is cheap to use and fills a niche in the available constellation of sheet products but in a perfect world there is no MDF.

Regards
Ross

I am with you on MDF...I like REAL wood

I like real wood like the next guy, but MDF has it's place.
Stable, flat, holds a machined edge, paintable and stainable - CHEAP

If you could find a plastic like SINTRA or PVC sheet that performed like MDF, I would be all in for the same price.

...off to clean that nasty MDF dust of my tool chest and control box (again) :)

Sean

Not so sure about HOLDING that machined edge Sean. The MDF that are dumped here in South Africa break easily when I machine contours etc that are smallish. Maybe other MDF is a bit tougher..sorry I have to go outside now to get rid of this MDF cough..:rolleyes:

I Agree,mdf is a killer I am at a stage where I don`t like the mdf projects because of the dust.You can have the best dust extractor the dust is still around.Like Sean said it is so versatile.Lucky thing is I know some chap up north with a contact for some ply boards.Kobus I don`t know if you got my sms about the cutting file for a bed that I created on the same concept as the pics I sent you.will bring it with and some cutters then we can try it out.( see you over the weekend )

How about Bamboo board? I seen a few pictures but I can't seem to find a Canadian distributor. Super strong and its a renewable resource.

Tim
Still climbing the learning curve ;)

LOVE bamboo...but takes a series toll on the cutting bits...but LOVE IT....did I mention I like bamboo sheet.

So true - like a moth drawn to the flame, that flat stable surface of MDF is just so tempting. cough ;)

Bamboo - I got my hand up for that.
When I can figure out how to draw a fin (not the outline the foil), it would be great to make a few bamboo fins like this one I hand made.
They are super strong AND they float.
This particular fin was made from flooring and still have a length of it in the shed waiting for the MM to cut some time.
Attachment 11477

Regards
Ross

Ross,

Could be worth digitizing the fin using a touch probe.

Im with Graeme,
If you haven't got a probe yet...spend a 100 bucks (buy) or make one. Its super easy to point cloud that fin and reproduce.

Good luck.

Sean - I'm lost on how the probe is driven and how the point cloud is manipulated.
Can you suggest something for me to read up about?

PS - I will scan one that is way better than my hand foiled version when I do find out how to do it.

Thanks
Ross

Ross,
First, if you using Mach 3, there is a place under ports/pins to assign the input on the pmdx to probing. (I use the same pin/port for the z-touchplate)

A good read is at : http://www.indoor.flyer.co.uk/probe.htm

buy one here: http://www.imsrv.com/deskcnc/probe.htm
or here: http://www.rockler.com/product.cfm?page=22582

and get the dxf and instructions to build one: http://www.cognitiveinnovations.com

Good Luck,
Sean

Other than using bamboo flooring does anyone have a link to bamboo board? I've had no luck looking

Tim

Thanks for the links btw, something else to add to the build list :)

Tim

Wrap the fin in tin foil and then treat it like touch plate . . . . . it really will work. :)

I use bamboo a lot
and is does not float . . .

www.bambooxl.nl - did a lot of CNC work for them. They have solid bamboo for beams, floors, staris, windows etc. Sorry only in Dutch for now.
Next week I'll make a lounce set with 80x80mm bamboo beams. 1 chair = 55kg, table 95kg. 1050kg m3 and exterior bamboo 1250kg m3.
Their slogan: 100% tree free.

http://www.moso-bamboo.com/ - mostly multilayer and veneer bamboo - for desks, cabinets etc.

Bamboo is hot in The Netherlands

Hans

Another Touch Probe build Here at CNCZone

Gerald,
Didn't think of that....but fantastic idea! You could use a sewing needle at that point for contact.

Thanks!
Sean

See this thread at SB forum: Probe

Check this out guys...came across this on ebay.
http://cgi.ebay.ca/CNC-3D-Digitizing...item3ca13f0832

Not a bad price either.

I can't track down the fin design software I downloaded some time ago (probably on a fried USB somewhere). Here's a link where you might be able to get it: http://www.geocities.ws/reystos/fin_designer/index.html
Here's a link to a useful helper app: http://www.grc.nasa.gov/WWW/K-12/airplane/foilsime.html
Regards
Red

Sorry about the late reply, but i don't get here too often. If you check the box for manual spindle control, it'll wait before cutting resumes. This will let you remove the clip.
Note that it will move back to it's previous position before waiting for you.

I can probably modify the macro, if you need it to stop right after zeroing the new tool. Send me an email if you want a modified version.

Gerry

Hans - yes it does AND it has three layers of glass and resin on it, that definitely does not float.
Water weighs 1000kg per cubic meter and dry bamboo is 300- 400 kg per cubic meter.
The big difference in density means that bamboo floats in water as it does not have the mass to displace the heavier liquid and sink.

Attachment 11505

Thanks everyone for your good ideas.

Gerald's foil idea seems the cheapest to implement so he is first cab off the rank.
I have loaded a Mach3 plugin for digitising and will see what happens.

Red it sounds like you have been having a good time of late at the ISA Championships. I will follow up the fin link.

Regards
Ross

Cheers Red

Got a fin out of the application - baby steps not sure it is going to give me quite what I want yet.
Your foils link is dead so here is mine, it has a cross section drawn for each foil and my eventual plan was to copy the foil and sweep it over a plan shape (somehow).
http://www.ae.illinois.edu/m-selig/a..._database.html.

No doubt you have a good working knowledge of this stuff as do the aircraft people. For the others who may not have come into contact with this ...

Using the NACA foil types one can reasonably predict the lift, stall and drag characterises (for the doubters that also includes in water using the Reynolds number for the foil).
NACA 6 series is the go for our application as one of the main design goals was to maintain laminar flow over the foil and reduce drag.
Laminar flow is simply the water sticking to the foil and not generating turbulence that in turn generates drag.
NACA eventually morphed into NASA and put a man on the moon, that's a pretty good heritage.

Regards
Ross

Hi Ross, I am also now looking at the spindles from LOVEHAPPYSHOPPING.. did you get more than one ER-20 collet with or did you buy them from somewhere else. From the eBay ad it looks like only one ER-20 collet is supplied.

Kobus, try and get hold of a Cromwell Catalogue, they are a UK company with an outlet in Jhb. Prices are generally quite good, local catalogue has ZAR pricing.

International subsidiary
PO Box 30137, Jet Park, 1469, South Africa
()27 011 397 6666, 27 011 397 6668 fax, http://www.cromwell-tools.com

or try these guys: http://www.avexair.com/tools_industrial.html

This is from thier website: http://www.cromwell.co.uk/IDX1449015K

Hi Kobus

Only one collett is supplied.

Ross

Hi Kobus
 

I was rushing out the door when I replied (for a Sunday surf), so a little more info for you on the collets.

Sets of metric collets are available on Ebay for around $50 AUD. You can buy them individually but after you have bought a few of the major sizes you have already paid for full set, so you might as well have all the sizes available.

Not for a minute would I suggest they are of premium quality at this price but for a first set they are more than adequate.

PS - liked you heart in a cage project too.

Regards
Ross

Thanks for the info. I suspected that only one collet is supplied. I have seen Metric and Imperial 'kits' on eBay.

Alan, I had dealings with Cromwell SA before...and they are not that cheap...maybe better quality than eBay but a bit pricy to my liking.

I would be careful with the collet quality.
I get mine locally & I prefer Japanese make & Taiwan made come in very close second.

Kobus,

try linearmotionbearings2008 on ebay. Chai sells the same spindles and inverters.

Just mail him what spindle and inverter you want, with all the collets you want, and extra nuts if you want. Also say where it need to be shipped to, and he will give you a price for it, and a direct link to his ebay store with all the products you asked for in a set.

Best regards
Sascha

Bedankt Sascha. Gaan nu kijken bij linearmotionbearings2008

Grounding The Braided Shield in Cables
 

Earthing
I was playing around with grounding the braided shield for the motor and signal wires on my machine this evening.
The Mach3 2010 screen set has a probe indicator on the home screen, with the shields not earthed I was able to get a pretty consistent flicker on the probe pin.
It did not do anything kooky and even probed to find the Z correctly despite the flickering of the probe indicator.

Reconnecting the braided shield from all the wires to earth completely removed the external signal noise that the Break Out Board was picking up on the pin.
Just though it might be useful to other builders to reinforce that earthing is important with your builds.

Inlay Test
I tried to inlay a bit of .8mm laminate into some MDF - turned out quite well.
Attachment 11564

3D Probing
Also tried some suggestions re probing a 3D object and was getting some software errors.
Have not had time to sort those out, so need to get a few other projects out of the way and return with my thinking cap on next time.

Mach3 2010 Screenset
A short note to say how impressed I have been with Ger's screenset.
It goes well beyond just making the screens nice, it gives some lovely function.
I like the one touch go to a toolchange position or go to a parking position.
The Z height probing works perfectly and the tool display path is massive.
Ger said he was going to do some updates, not only did he do that, he sent me the updates when he had done them !!
Similarly he did some bug fixes that related to a specific version of Mach3.

I don't know Ger, don't work for him etc etc but he has given me great service and his screenset is really headed in the right direction to automate CNC machinery for a tiny price.
Worth a look at http://home.comcast.net/~cncwoodworker/2010.html

Regards
Ross

Nearly a month since my last post, must be spending to much time annoying the other Australian builders like Red Boards and Tangocharlie :D

Enough of those nicely completed works so often seen on the forum - how's this for a disaster.
Attachment 11772

It was all going fine until the heat built up so much that the chips were remelting before I could suck them out.
Once I unscrewed the block it was clear just how hot the aluminium had become - really really hot.
Initially I was quite confident as I had used some feeds and speeds that Dmitry had posted.
Next attempt I will use compressed air to clear the chips AND cool the workpiece.

Note how cleanly the 4mm hole cut with a 3mm end mill, I suspect this is because it had some clearance for the chips.
One day I will cut aluminium well but just not today.

Regards
Ross

Ross - maybe you got the wrong aluminum alloy, usually folks hear swear by 6061 T6 grade for good machining