The Shop => Composites & Plastics => Topic started by: Dawai on December 20, 2014, 07:22:02 PM

Title: 3D printer, gantry machine, casting models
Post by: Dawai on December 20, 2014, 07:22:02 PM (

My 3d printer, been keeping me busy working out issues, bugs, changes. It is getting closer, The Leveling bed,  the temp controller for the 23x24" floor-concrete backer board nichrome wire sandwich hotbed is to be wired next. Not the screw adjustable Z home limit for varying print height. Note the single X axis motor with dual shaft-belt drives??

Plan was for a 3d printer for sand casting models, acetone "slicking" of the abs prints and Lost-PLA casting. For continuing my hotrods and Harley hobby a bit longer. Each day I get closer to "DONE" with everything.  I thought I could carve with this machine too, I bought a Bosch router.. I was wrong, too damn slow cutting wood of varying hardness.. perhaps some of you other guys have enough patience for slow-motion work, but not I.   I chucked the 2hp router in the cnc bridgeport and went on with it.
Title: Re: 3D printer, gantry machine, casting models
Post by: Brass_Machine on December 21, 2014, 09:38:07 AM
Do you have pictures of your printer?

Title: Re: 3D printer, gantry machine, casting models
Post by: Dawai on December 21, 2014, 10:24:44 AM
A few, mostly videos these days thou.. here are some I took time to resize this morning.
Title: Re: 3D printer, gantry machine, casting models
Post by: Dawai on December 22, 2014, 06:13:58 AM
I have a STC1000 temp controller, fixing to wire that up to the hotbed I think.  Not real impressed with the accuracy I am getting through the Chinese electronics tied to the megatronics-arduino, hotbed or extruder.  It is a K thermocouple.. so it may get replaced with a spare PID like I put on my beer brewer.

If I had this to do over? it'd be a delta printer. When I started planning this, there was not enough information on the tuning and calibration of the delta-angular motion printers.  That is the best way to get a huge build area without eating up a large amount of floor space.  I had this xy axis on a stainless tub, unfortunately it sounded like a amplification drum for the singing the steppers made.  You could not bear to be close to the thing while it ran.

I bought 5lbs of injection blue wax, going to try later after the holidays to build a decent heated-tube wax extruder.  That will involve making a quick-mount for the heads.

Still happy with the V-slot & extreme rollers from openbuilds.  You could build a real nice Delta bot using that in half the time I have messed with this gantry.
Title: Re: 3D printer, gantry machine, casting models
Post by: vtsteam on December 22, 2014, 09:34:39 AM
Dawai, what is a delta carriage? Does it use an angular coordinate system?
Title: Re: 3D printer, gantry machine, casting models
Post by: Dawai on December 23, 2014, 07:42:14 AM
Yes, using the Openbuilds xtreme rollers and Vslot extrusions there is very little to build.. you stand 3 aluminum extrusions up vertical, connect in a triangle, install the carriages, the end clevis's to the center, as calculated each of the 3 axis motors drags the carriage up to make the angular positioning.  When configured right, the 3d printer head travels parallel to the build plate on the bottom.  MUCH simpler build than a normal x-y-z axis Cartesian machine. Less parts, less complication except the math.  Plus the build area? you can make the verticals as tall as you want to.. no loss of structural integrity. (search gigante printer on youtube)

The Math is crazy, but if something else calculates it, no problem. Using the formula in the Marlin-arduino firmware you could do a simple bot with a some servos and gearboxes for a couple of grand, you know like the one the company I worked for in the 80s paid millions for??

My extruder temp sensor on the Chinese megatronics board died.. I am so frustrated.  Chinese electrical products are crap, or they sell us the crap and keep the good stuff.  I lost a 12vdc power supply on the solar-lights here.. and the heat sensor on the megatronics board yesterday.  The pile of junk stuff smoked is growing. All surface mount stuff a old near-blind guy can't fix.

This whole system is going back onto the Mach3 drive and control.  You can slicr the 3d files, and run them on a computer. I'll run the heat on the two pid controllers. If that don't work, I got 1980s opto22 analog boards that talk on a serial link, done worked out Mach3-serial communication.
Title: Re: 3D printer, gantry machine, casting models
Post by: vtsteam on December 23, 2014, 08:49:16 AM
I don't think the math would be too difficult to write a Cartesian G-code converter in an Excel spreadsheet. You'd pull in the XYZ numbers, and output the 3D polars (deltas?)

I've done that kind of thing before for a 4 axis hot foam wire cutter when I got fed up with some crap software I'd purchased for cutting model plane wings. I like Calc (freeware Excel style spreadsheet) for doing custom design stuff. It's easy to use, and with Libre Office, can run on any OS.

But what I do wonder is how such a framework would have sufficient stiffness? I can't see it being useful for something like milling where there is heavy side forces against the head. I guess it makes sense for a 3D printer, where side stresses are only inertia.
Title: Re: 3D printer, gantry machine, casting models
Post by: Dawai on December 23, 2014, 03:32:07 PM
Some success, some failure.. the megatronics is back in a box, it lost the reference in the thermocouple circuit.. the Cheapie parallel port Mach3 breakout board is half hooked up and tested operating the drives. (extruder drive is not connected yet)  It currently has only home switches and I have not hooked them up yet.. they normally series on a mach3 system.  I want to use this high speed system to scan-probe 3d objects also..   

THE hotbed, 24 passes at 24" each made 24 ohms (TemCo RW0063 20 ga nichrome wire).. I tried it on 3 sets of 24 volts windings.. it only got to 40C.. I hooked it up on 120 ac (more dangerous) and it got to 60c.. I'll have to rig in a ground fault circuit to be safer.. and be aware.  I can of course use a hot water heater thermostat and put the digital one back in the box.. or use it for a temp indicator?? or??  THE hotbed from what I understand it just to help adhere the first layer..

Looking, the cnc protoneer Arduino CNC shield looks like it can be used stand alone, pump 5 volts in, the drive power in, and use the small poulu drives for small motors.. At $12 this is the cheapest way to drive small motors with a computer..

Title: Re: 3D printer, gantry machine, casting models
Post by: Swarfing on December 23, 2014, 05:26:35 PM
If you are having problems with the BOB then join me in the same boat. Had to just work through the understanding of the pinouts. All in all though a nicely put together board short the documentation around it. I can help a bit here from my thread over at the zone.

Title: Re: 3D printer, gantry machine, casting models
Post by: Dawai on December 24, 2014, 09:01:13 AM
Yes, I'm not much help, the jumpers on the board, no documentation. "A932A" is the board "silk screen" and you can find some stuff if you can wade past all the "gotcha" redirection links to ebay sales pages. Jumpers sometimes do not matter, okay in the default position, but I did smoke a new vfd about twenty years ago and I never forget a mistake.

You have the usb providing 5volt signal power? you have the additional external power connected to the terminals below the relays??  Also, how to provide "pin labels" for Mach3 for the output relays>>>? all the 12 output pins on a parallel port are used? the 4 inputs, there are some questions not answered yet..   (edit after thought).. and there was four bits of bi directional pins that input and output... on a parallel port interface.. I see no "cpu" to read the usb and create logic.. so??  Normally Pin 1 is the "strobe" port pin used for vfd pwm... that is also used for a 0-10/5 volt signal..  but pin 1 was on the ttl step terminal strip.. so???

I bought this board cause it had both connections for sink, or source logic stepper drives, I have both now, and I have some servo drives I bought over ten years ago I plan on using also.

(10:22 edit)...  Mach3, OKAY.. use Pin 1 for PWM output, abandon it on the terminal strip.. set it up in Spindle configuration, set it up in Pins Outputs spindle control.    THIS board is a either or configuration.. use the pins for 6 axis, or less axis and use those pins for relay control..Removing jumpers disable the terminal strip,  If I am wrong, please let me know..


1. High integration;high reliability
2.Absolute voltage isolation. The CNC control board is powered by computer USB port used as digital power that disgned as common cathode and common ancode
which is connecticed to motor dirver’s common port,and another power is DC 12V to DC 24V which is used as analog power.It’s much more safe and stable by isolating the digital power from analog power.
3.Five signal ports are isolated by optocouplers which can be used as limitting position,finding origin points,starting and Estopping. There is no interruption with isolation of optocouplers.
4.Twelve output ports can control six motors simultaneously,and they are also can be used for some ports as you like.Some ports are communally designed for two functions,choice should be made if you
want to use them.
5.Three relays are put on the board that can be programmed in the mach3 software,and there are three leds used for pilot lamp.The relays can be used to control external equipments such as solenoid valve, cooling pump and so on.
6.Programmed analog voltage from zero to ten volt can be set.The analog voltage can control the speed of spindle motor.
7. The CNC control board can control step motor diver with common cathode or common anode.It also can control servo motor with digital signal.
8.The analog power can be from nine volt to thrity volt.