Last year, I purchased a Techno-Isel DaVinci router from one of the
local high schools. Not sure why they decided to sell it. Either the
instructor retired, the curriculum changed, or student interest waned.
Regardless, it caught my eye. These machines are well-made.
I intend to use this machine to learn as many aspects of cnc machining
as possible. That includes not only the machine itself, but other things
such as design, numerical control software, material science, prototyping,
etc.
Although it's designed to cut wood, there should be no problem
modifying the z-axis assembly to accomodate filament extrusion, laser
cutting, or other x-y-z applications .
Finally, to teach is to learn. To that end I'll try to share as much
as I can via images and video.
~john
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The sides of the gantry contain the motor controller and power supply. Each is covered
by a thin aluminum plate attached with machine screws and plastic stand-offs. The
covers do not keep the sawdust out. At least I know this machine was used.
The motor controller is on the left side.
The power supply is on the right side.
Motor controller showing stepper connections. Each stepper is six wire.
Inside dimensions: ~ 160mm W x 185mm H (as a rectangle)
~john
Removed the t-slot work surfaces from the x-axis and z-axis.
There's sawdust everywhere. To be expected. Probably inside the x and y assemblies too.
The x-axis work surface is a little scratched up. The back side is like new.
I used Dawn dishwashing detergent. Did a good job. I'll look for some aluminum cleaner and wax tomorrow.
The z-axis front and back are like new.
The outside of the x-axis assembly turned out nice too.
~john
The best thing you can do to that machine is to convert it to run Mach 3 with g540 motor controller. I ran a stock techno for years with the standard g code interface. It was horrible. I then stepped up to running it with the standard electronics and a controller called Gallad with the Kay interface. Finally I bit the bullet and converted it to run mach3. I now get full use of the machine with incredible speed, power and features like spindle speed control and a Z touch off plate.
In retrospect, I should have done it years ago!
http://www.glenspeymillworks.com Techno LC4896 - 2.2Kw Water Cooled Spindle | Moving Table Mill from Omis 3 CMM, 500Lb granite base | Epilog Legend 32 Laser Engraver
Hi Pplug~
Thanks for the note. The steppers and controller will be replaced in the near future.
I'm not going to use the Mach3/G540/Parallel Port toolchain. I know it's popular and a reliable solution,
( I have no bias against it ) but I'm doing this to dive deep and learn. Especially the software.
The stepper motors are nema 23 with holding torques of 120 oz/in. There are some good solutions
available that will allow me to tinker with this thing 'til I break it.
Before I replace the stepper motors I need to know their actual resolution. The machine
specifications state that the current motors achieve 400 steps/revolution (0.0004 in/step)(0.01mm/step)
with zero backlash.
Without power, you can turn the steppers and feel each step. I marked the wheel on the outside of
the y-axis and counted each step as I turned the motor a full 360 degrees.
200 steps. I'm guessing the controller handles the 1/2 steps. This is very encouraging. 0.02mm is 20 microns.
I wanted to see what 0.02mm per step looked like, so I setup a Velo 400x usb microscope and took a picture
after each step. Here are 25 steps covering a distance of 0.5mm. The point is the end of a pin.
Here's the setup.
~john
Got a chance to clean, re-grease, and re-oil the z-axis.
It took me a while to understand the types of compatible grease and oil. The
maintenance manual listed a number of options. I had to check the msds pages for each.
I chose Coastal all-purpose lithium-grease #2 from Warren Oil for the ballscrew and
Coastal Hydraulic and Jack Oil (AW 32) for the shafts.
I cleaned everything with FVP degreaser.
Then applied grease to the ballscrew and oil to the shafts.
Overall, I think it turned out okay.
~john
Four bolts on the bottom hold the x-axis in place.
Hard to clean without removing the assembly. Needs to be done.
Interesting design. Double linear shafts on a custom extrusion.
The ball bearings inside the linear half-blocks(?) don't roll smoothly.
The X and Y axis assemblies seem to have identical designs.
~john
A lot more work involved here. As I suspected, the x and y axis assemblies are identical
with the exception of how the y-axis attaches to the gantry columns. To clean this
I decided to disassemble the whole thing. Why not, I was already there.
Pulled the bolts, removed the column and cleaned it.
Had to remove the motor to get at all the bolts.
The connector is for the limit switch.
The green board terminates the connections to the motor.
Removed the covers. I doubt it's ever been cleaned.
Removed the assembly from the gantry column.
Cleaned up nice.
Greased the ballscrew and oiled the guides.
Ready to be re-assembled.
~john
Wow there is a lot of sawdust in that x axis! We have been running ours for years with little to no dust collection and don't have anything like that in ours! The one thing I have to really give techno credit for in the past is the excellent protection they give their linear motion components. You can't say that about the new Chinese stuff they went to.
http://www.glenspeymillworks.com Techno LC4896 - 2.2Kw Water Cooled Spindle | Moving Table Mill from Omis 3 CMM, 500Lb granite base | Epilog Legend 32 Laser Engraver
Hi Pplug~
I was surprised too. Expected it to have sawdust inside but nowhere near that much. The
maintenance manual recommends greasing the ballscrew *through* the rubber flaps.
You are right 'tho about the components. They are first class. My understanding is the ballscrew
and nut were made by THK. A comparably priced pair from McMaster Carr would easily run
north of $500. This machine has three.
Working on it has given me an appreciation of the benefit of using quality parts.
~john
Bolt left side gantry column to base. Brushed a little oil on each bolt.
Re-attached Y-Axis, ballscrew and limit switch.
Attached protective covers.
Re-mounted stepper motor and limit switch connection.
Attached coupler to ballscrew. Tightened screw through hole in cover.
Re-attached right gantry column.
Re-attached X-Axis assembly -- four bolts.
Mounted Z-Axis assembly -- four bolts.
Attached protective covers.
Mounted Z-Axis surface plate -- four bolts.
Installed spindle mounting bracket.
Installed spindle. Re-tied power cable to stepper motor cabling.
Mounted X-Axis surface plate and gantry side covers.
Performed a power-up self-test (hold start button on power-up) -- worked fine.
The controller is still a problem 'tho. I'm willing to tinker with the serial
connection and write a little program to move the motors but that's
about it. If it doesn't want to cooperate it's on to plan B.
~john
The davinci uses a non-standard serial cable. You can wire up your own by using the diagram in the manual. You shouldn't have to write a program to make it move, just download the stepper code interface from techno's website. The interface works, but is not feature rich. The largest handicap of this machine is the serial interface on the motor controller. It is ridiculously slow when running complex or large toolpaths.
The router has two ways to download and run a tool path. First you can "drip feed" the gcode, Line by line. The second is downloading the code to the small internal memory.
The best thing you can do is replace the motor controller all together.
http://www.glenspeymillworks.com Techno LC4896 - 2.2Kw Water Cooled Spindle | Moving Table Mill from Omis 3 CMM, 500Lb granite base | Epilog Legend 32 Laser Engraver
Pplug~
I have the serial cable supplied with the machine. Matched the baud rate with the dip switches, etc.
Plan B.The best thing you can do is replace the motor controller all together.
~john
Purchased a SongYong Hybrid Stepper Motor and a Pololu High Current Motor Controller.
The controller has a TI DRV8825 stepper motor driver -- 4.5V, 2.0 A per coil. The
stepper's holding torque is 190 oz/in, so I think I'm above the spec for this machine's
current steppers. Although I'm still unsure.
The DRV8825 requires a heatsink to run at 2.0A per coil. Sparkfun sells "finned" aluminum
heatsinks which I've seen used with RAMPS boards but I wanted to make one out of
copper just to see if I could.
I cut a 10mm piece of 1/4" copper tube and filed it to create a flat spot.
I'll attach it with thermal adhesive tape.
This is the fourth version of this heatsink. I drilled holes and cut slits in the others
but I like this one best. Easy to make and looks good.
~john
I just learned that I'll be getting one of these tomorrow, through a trade deal with a friend for some light machining work. A CNC has been on my list for years, but the acquisition of a manual lathe, a mill, and a surface grinder put it off until now. This is rather sudden an unexpected, but I'm very excited about it.
I understand that these are very well constructed (mine is reportedly from 1997), with quality ballscrews and so forth, but the consensus seems to be to replace at least the controller. Anyone recommend one that would be reasonably "future-proof"? I'm hoping to run this from a little netbook or an older MacBook Pro if I possibly can (making use of what I have, saving budget for the machine upgrades), so no serial port available.
I'm not sure what the recommended load/use is. I believe we had one like this in my high school (half my life ago), but only ever saw it milling plastics. I would like to be able to do some brass and aluminum parts at least, if not steel on occasion. With upgraded motors and controller would you expect this to handle such applications? If not, what is the weak link? Would it be conceivable to upgrade parts (made on my lathe and mill) to get it to that point? I realize it won't be as rigid as my manual mill, but I'm hoping to use this to make precision parts for things like a dividing head for the mill (among many other things).
Thanks for the patience with the ignorant questions. Normally I would do a lot more homework before getting something like this, but the deal was just too good to pass up, so I'll take it and then figure out what I can do with it.