[tahustvedt]

the PC parts arrived today so I immediately assembled it and installed Winders! It's up and running now. I need a mouse pad because the optical mouse didn't like the surface of the table. Too shiny I guess.

[tahustvedt]

I made some stuff for some friends.

A friend of mine drives a BSA motorcycle and wanted a sign for his toolbox. I cut this from regular 2 mm aluminium.

The helicopter cartoon is a freehand bitmap drawing I made a while ago which I traced and cleaned up in VCarve and carved with a V-bit. It was cut from 5 mm 7075 aluminium with a 6 mm end mill.

I used 4 mm plexiglass to make the Scania V8 emblem for a friend.

[tahustvedt]

Here's a video of the machine cutting out a jig for making a propeller system for my RC planes. www.enrarot.net/videos/cnc/cnc02.wmv

[rlrhett]

I very much like the idea of integrating a CNC into a table or workbench. Mounting through slots seems to solve the problem of exposed rails catching on things if you use the work bench for other things.

What I didn't quite get was why you have the internal "walls" that parallel the slots. They don't seem to add anything structurally. Can you tell me what you added them for?

[tahustvedt]

They were made mostly to keep the dust and chips from going everywhere, especially down the slots in the table. They are very useful when I mill aluminium as the chips fly when I don't use the dust shoe, and spraying the part with WD 40 makes a mess.

[studysession]

I made some stuff for some friends.

A friend of mine drives a BSA motorcycle and wanted a sign for his toolbox. I cut this from regular 2 mm aluminium.

The helicopter cartoon is a freehand bitmap drawing I made a while ago which I traced and cleaned up in VCarve and carved with a V-bit. It was cut from 5 mm 7075 aluminium with a 6 mm end mill.

I used 4 mm plexiglass to make the Scania V8 emblem for a friend.

This is funny. Did not realise that you were same person I have been talking to on the Vectric Forums. So what of their products do you have? I purchased the bundle of all three VCarve, Photo VCarve and Cut3D.

Love the work you have been doing. very nice and keep it up.

[tahustvedt]

So far I only have VCarve Pro 4. I bought it before the price raise. I will probably get Cut3D soon as well.

[studysession]

So far I only have VCarve Pro 4. I bought it before the price raise. I will probably get Cut3D soon as well.

Cool - love your work.

[tahustvedt]

I bought Cut 3D and started doing test-cuts of propeller blades for my big P-40 the past week. It's really easy to use.

Yesterday I made a semi-automatic tool adjustment. An aluminium plate is placed under the tool and I just jog down the Z until the tool touches and electrical contact is made which closes the limit circuit. The cable I used is a phono extension cable I had lying around. I cut it at the female end and installed the female connector on top of the gantry and used the opposite end to make the sensor-cable with a crocodile clamp to clamp the tool. I got the idea of using an aluminium plate and checking for continuity from a CNC-user on a norwegian RC forum. I'm sure something similar's been done lots of times before. Once the tool touches the plate I type in the thickness of the plate in the Z-coordinates on the screen.

[Buzz9075]

If your router is grounded you might find that you can attach the one clip to anywhere on the router or the ground connector thus removing the requirement for you hooking up the one clip to the cutter. I know my router I can connect one end to the house ground and the other end to the test plate and it works fine.

[spalm]

Hey Tahustvedt, nice work. Very clean machine.

I really like the touch plates also. If you screw two small plates together but offset, you can set the top one on the top of your work piece, and then touch the bottom one. This will set you exactly at 0, without having to enter the thickness of the plate.

If you use several of short pieces of aluminum angle, you can do XY zeroing also. Just stack them inside of each other so that the outside piece is moved back one half the thickness of your bit. Hold them (or rubber band them) to the corner of your work piece. Now touch the inside of the outside piece and click zero. This also works with straight plate, but I find that I can hold the angle perpendicular easier.

It is probably best to remove the wire when using. They are double insulated for a reason.

Steve

[tahustvedt]

Thanks for the tips, guys.

I removed the tool-clamp now and it works fine just touching the plase as the machine is grounded.

[tahustvedt]

I've been without a spindle for over two weeks now. The cheap one I used before suddenly died on me in the middle of a job. I got a Kress 1050 FME to replace it and boy is it great!

The collets are very precise and it runs smoother than the cheap one. The RPM compensation works well too.

A short video: http://www.enrarot.net/videos/cnc/cnc05.wmv

[tahustvedt]

Today I added a stiffener to the Kress spindle. It seriously stiffened the spindle plate. I milled it out of 8 mm thick aluminium.

[tahustvedt]

A lot of water has passed under my bridge since I built this machine and I'm getting the hang of it now.

Lately I've milled out lots of RC helicopter rotor blades out of oak. It wasn't as easy at it would seem before I started but I have developed a technique that keeps the thin and long parts supported during the process while letting the machine do all the work with no tabs to clean up afterwards. The two blades pictured together below are 350 mm long.

I have also used the machine to mill a four bladed RC helicopter rotor head out of aluminium for testing purposes since I'm going to make a large helicopter with five blades later on. Ill make a new, improved and more compact version soon.

The six bladed tail rotor for the large model is already finished and is pictured assembled below. It has a 294 mm diameter. The blades are made from oak with fiber glass root doublers. The hub is made from 6082-T6 aluminium.

[studysession]

That is very impressive. Nice work.

[joecnc2006]

can you do a write up on how you cut then and also how you use no tabs?

Joe

[tahustvedt]

The software I use are Discreet Plasma for CAD, Vectric VCarve and Vectric Cut 3D for CAM.


The rotor blades were made as follows. To draw the blades I first lofted a profile, then I booleaned away some bits at the root and tip, and made a root mounting surface shape.

In the drawing you see some 2D shapes around the blades. These ar for vutting out the alignment holes and bolt holes in VCarve 4.5. The two 6 mm holes, one on each end of the parts, are used for precise alignment when I turn the piece around. The four smaller holes are used for securing to the table with screws. To keep the 3D and 2D drawings alogned I always center the center of the part to the "world" zero because that keeps them aligned in both Cut 3D and VCarve.

In Cut3D I create separate profiles for the top and the bottom surfaces because that gives me more control of the process and placement in the material. I don't like to use tabs on the blades because they are so thin and it's difficult to get the tip shape just right when I sand down the tabs afterwards. The process is as follows:

1 - Drill the alignment holes and bolt holes using the Vcarve code.

2 - I make the bottom of the blade first. Since these blades are flat on the bottom I cut the bottom of the blade into the surface of the wood, as shallow as possible. That way it lies flat on the table after I turn it around so that it has better support. I don't create a roughing pass, I just finish right away with 0.2 mm stepover and raster along X, which is along the blade.

3 - Then I turn the blade around and do a Z level X raster roughing pass to get through the 14 mm thick piece of wood. I use a 9 mm silhouette and 5 mm machining allowance here because that leaves enough material left on top of the blades to hold them flat on to the table as they are milled, and the silhouette makes sure the finishing tool doesn't have to dig through the full thickness of the wood later on.

4 - After that I do a finishing pass like I did on the bottom surface. Raster along X with 0.2 mm stepover. Since the bottom surface of the blade was milled flush with the surface of the wood that's now lying against the table, and since the roughing pass left 5 mm of wood on top the blade is supported all the way and won't flex up or down while it's being cut. I have to cut a few mm into the table to cut out the shape completely because I use a 6 mm ball end mill.

5 - To make sure the blades stay put without tabs as they are cut out I use clamps. When the machine has almost finished a blade I put three clamps on the table to hold the trailing edge of the blade down along the blade as the last few mm of the leading edge are milled out. I just pause in Mach 3 when the raster it at one end and continue after the clamps are on.

It takes between 60 and 90 minutes To cut two blades.


I made a little video which shows the machine miling the aluminium hub:
http://www.enrarot.net/videos/cnc/cnc08.wmv

[.xXACEXx.]

your cutting a pretty good variety of parts on your router, nice looking heli parts...i like the setup after rereading your post...it was only a few month ago you "wanted a cnc router" now you got one thats cutting well ,on a side note i had a rc heli one time it needed some attention,which i never gave it i traded a pontiac fiero for it,..kept it for about 10 years ..the whole time needing rotor blades..which i never bought...was to afraid to crash it ...it was a schluter mini-boy pretty kool little heli,,any way...a few month ago i traded it back to my uncle for a rc stadium truck...dangit i never even flew that thing ...nice looking router..hows the xylotec board treating ya?..what kinda rapids can ya get?...whats your lead screws pitch (1/2 10 acme???)..in a earlier post it looked like your y axis screw wasnt supported on one end,is that working with out any backlash?.....again great router ya got there!!

[tahustvedt]

My controller isnt' a Xylotex, it's a similar board based on the A3977SLP chip. It works great but it will overheat and lose steps if it's very hot in the room. There are no heat sinks on the chips so I'm considering putting on a few and a fan.

My screws are ball screws for the X and Y and a Universal Thread precision lead screw for the Z. They are all supported on one end only by angular suport bearings. The X has a 15 mm ball screw with 10 mm lead and two ball tracks. I think it's rolled but I'm not sure of the accuracy. It's a THK unit and has no backlash after I reballed it. The Y has a 15 mm C1 ground ball screw with 5 mm lead and no backlash at all. The Z has a very precise high quality 12 mm lead screw with a 5 mm lead. It has a little wear in a certain range in the middle so there's a little bit of backlash there, but outside the middle there's no backlash as far as I can tell.

I'm not sure since it's a while since I configured the motors but I think my rapids are 6500 mm/minute. It races across the table in a few seconds.