Topics

21

General Mach Discussion / Z Axis Help Appreciated!!!!!

« on: January 21, 2012, 11:34:16 AM »

Hey Guys,

I want to get your thoughts one more time if I might!!!!  Its been a little over a year since I tackled building my own cnc wood router.  For the most part have been been extremely pleased, and everything has done exceptionally well.  I did run into an issue with z axis motor slippage right out of the gate.  It didn't really supprise me at first because I had concerns that this might happen.  I build and design equipment at work and alot of my design was based around some spare parts we had from older equipment that had been decomissioned.  LM guide and things of that nature that really elevate the cost of building one of these.  As I began calculating the cost of this machine I opted to make the spindle lead screw out of a precision acme screw with an acetal anti backlash nut.  Once assembled I realized that there was a large amount of friction which in turn would lead to loss of motor torque.  I didn't really worry about it much, as I decided that eventually I would end up with an old servo that I could rob the ball screw out and retrofit into my application.  When I started running the machine I started loosing steps immediately on the z axis.  I changed my timing pulleys to give larger gear reduction and then decreased the resolution on my stepper driver.  The stepper motor is a 425 oz. in. in case any of you are wondering with a one and five twist 1/2 precision acme screw.( I believe that's correct on the acme screw, its been awhile!!!!)  Once the motor was retuned and calibrated that took care of most of my problems.  I turned down my rapid speeds in my cam program and haven't had many more issues.  I had no intentions of making what I actually have been on this machine.  Funny how things work out.  Gunstocks seem to be pretty lucrative to me and fun.  My initial thought were name plates and maybe some small relief work.  Now that I have bored you all to death I will get to the point!!!!  When finishing one of these units there is an extreme amount of time with start and stop points and moving to them.  So when you combine this with slow rapid movements that really creates a long run time.  Now to avoid alot of sanding you only finish with ball so fast, but rapid can be as fast as the machine can stand.  X and Y can rapid at 200-300 IPM with no slippage, but the best I can do on Z is about 90.  Now in my cam program I can only set the rapids overall, not by individual axis.  So in turn this slows everything down.  I have checked every possible potential failure that could cause the z to slip and cant find anything it could be except the motor and that there is just to much mass to be shifting very quickling with the additional friction of the lead screw nut.  That ball screw I was waiting for hasn't happened yet so I have decided to go with a larger stepper with its own power supply.  I thought about isolating the Z axis with its own power supply and trying that first.  I haven't put an amp clamp on it to see what its pulling or if its getting the power it needs.  I bought a four axis kit from Keling and all steppers are using the same power supply.  Y gantry are two steppers slaved together  and X is just one stepper.  I am enclosing a picture of my z axis assembly so you all can see and maybe shed some light.  I am certain I have over killed the replacement stepper motor.(1600 oz. in)  It want to increase the resolution a little more than on the previous and just want to be sure I have enough power.  Everyone's continued  help on this forum is greatly appreciated!!!!

22

General Mach Discussion / Mitsubishi MR-J2S-40A and Servos!!!

« on: July 12, 2011, 11:13:43 PM »

We are doing a retool on a machine at work and are going with the next latest greatest Mitsubishi Amps and Servos.  That being said I will be able to acquire enough of these to build another machine.  My first machine was built with stepper motors and even though I haven't had any issues, I would like to build a larger one with these servos.  The drives are Mr-J2s and I believe that the motors and gear heads are HCkfs43.  I was curious what type of Bob to incorporate  with this build.  My other  machine uses a C10 bob, and I haven't done enough research yet to see if it is feasible for this one.(Voltages, ETC.)  I typically do the mechanical design at work and the build and leave the electrical to the programmers.  I had a blast building my last machine from start to finish but did pull my hair out a few times due to ordering some components that was exactly the best for my application.  I was hoping to get a little bit better plan together for this and avoid some frustration.  Any input would be greatly appreciated.

23

General Mach Discussion / G-Code Help!!!

« on: June 27, 2011, 09:33:12 PM »

Let me start off by saying that I am by no means what I would consider  a programmer.  I am a conventional tool maker by trade going on twenty years.  A few years back I started doing 3d modeling and then shortly after I was thrust into cnc programming working off part geometry in models.  I use Alibre Cad/Cam and it was pretty much there it is heres the machine and let us know if you need anything else.  Of course as painful as it can be sometimes the hard way isn't all ways the bad way.  Memory retentions seems to improve with hard lessons.  Last year I decided to build my own cnc wood router.  I done all of the design work, build, and wiring. Alot of help was provided by other users posts, as most of the problems I ran into had already been answered here.  Machine is running good, finished my first gun stock this past weekend.  The 3d contouring worked great and everything was up to par.  The only problem I had is that I can't drill holes.  I know sounds stupid can cut a 3d contour but can't drill a simple hole.  That's what I thought!!!  It would travel to all the points where the holes should have been but then set there momentarily then move on the the next one.  No movement in the Z axis.  I remember in the set up of my stepper motors that it said something about setting them up as a Sherline.  That being said when I picked my post processor I choose Mach3-Sherline.  Not to say that I am right in doing so by any means, just hoping someone could possibly point me in the right direction if I am incorrect.  Everything else on the machine is working great.  I am attaching a simple drill program(break chip) that I wrote for an example.  I have looked I can see where you can edit your post processor, but being fairly new to Mach 3 I don't exactly know what I might need  to change.  I am hoping that some of you guys that wrote g-code before cam packages were available could look at the sample program and point me in the right direction.  Thanks for all of the help, this forum rocks!!!


N1 G00 G49 G40.1 G17 G80 G50 G90
N2 G20
N3 (Breakchip Drill )
N4 M6 T5
N5 M03 S8000
N6 G00 G43 H1 Z1
N7 G01 X0.8750 Y-0.7500 Z0.2870 F3000.0
N8 M8
N9 G00
N10 G73 X0.8750 Y-0.7500 Z-1.108 R0.1 L0.0 Q0.1
N11G80
N12 G00 Z0.2870
N13 G73 X3.1250 Y-0.7500 Z-1.108 R0.1 L0.0 Q0.1
N14G80
N15 G00 Z0.2870
N16 G73 X3.1250 Y-3.2500 Z-1.108 R0.1 L0.0 Q0.1
N17G80
N18 G00 Z0.2870
N19 G73 X0.8750 Y-3.2500 Z-1.108 R0.1 L0.0 Q0.1
N20G80
N21 G00 Z0.2870
N22 G00 Z1
N23 M5 M9
N24 M30

24

General Mach Discussion / Shuttering 3d Contour!!!!

« on: June 18, 2011, 11:22:03 PM »

Guys I hope some of you can help!!!  I noticed this afternoon that my machine was really slowing down and shuttering on the 3d contours.  I don't know if it the acetal nut on the acme shaft heating up as it runs causing drag the motor down.  All axis seem to be waiting on the z axis.  I thought it was my program but I reverted back to settings that I had ran earlier this morning and the seem problem still seemed to exist.  Could be a voltage problem?  I am at a loss.  I am going to run the program in the morning on a fresh start up to see what happens.  The problem seemed to get gradually worse as the machine ran.  I am running a keling 425 oz inch four axis kit with the 36 volt power supply.  Three to one gear reduction on all axis.  1/2 acme screw with acetal nut on the z, dual drive y axis slaved together running on rack and pinion, and the same set up in x as y with one motor.  Don't seem to be loosing any steps and work is coming out slick as a ribbon but the shuttering really is slowing the program down.  Hopefully someone has the answer because it is driving me nuts.  I even noticed this same shutter in my roughing programs as well.  As I said I didn't have any of this when I started running my machine this morning.  I am attaching some pics!!!

25

General Mach Discussion / 4th Axis Rotary Table!!!

« on: May 04, 2011, 09:32:27 PM »

I am getting ready to start putting together a rotary table for my wood router.  I do some fourth axis machining at work and would like to add that capability to my router at home.  I was planning on purchasing a phase II rotary table and retrofitting it with a stepper motor.  My question is:  Have any of you done this and how difficult is it to get set up and going in Mach 3 and is my choice selection the correct one or is there a better option?  My current configuration has two stepper motors slaved together on the Y axis(rack and pinion) and one for the x and z axis.  Any advice and input would be greatly appreciated.

26

G-Code, CAD, and CAM discussions / Cad Software!!!

« on: February 09, 2011, 09:30:14 PM »

Guys, I have another question that I could use some input on.  I currently use Alibre CAD/CAM.  I have the expert version of each.  After realizing that Alibre was crippling my cam software(Visual Mill 6.0) by limiting its import options to what Alibre could open I starting looking for alternatives.  Don't get me wrong it works great for most industrial metal working apllications, but not so good for doing art type work on my new router.  I thought I could do at least basic v carving from imported dxf files but the problem elevates when trying to paste the dxf into a part file which you must do to get it in the cam package.  Most of the time if it there is many lines it locks up the computer.  I thought maybe it was my desktop at home so I tried on my workstation at work and pretty much had the same results.  After much debate I went ahead and purchased a bundle which inlcuded v-carve, photo carve, and cut 3-d.(Vectric Software)  I would have liked to  purchase Aspire but it wasn't really in my budget.  So far the software seems really great and I have picked it up fairly quick.  My question is there any programs out there that I can use for creating some 3d relief files that won't break the bank?  Maybe a freeware version that I can use as an interim.  I know that you can purchased 3d models through Vector art and import to give some more creativity but I would rather do all of my own drawing.  After having several thousand dollars tied up in software already I was hoping to get some good input from people already doing this type of work.  The hole art type work is new to me and 3d machining is something I do on a regular basis in metal just not wood.  Any help would be greatly appreciated.

27

General Mach Discussion / Need Help with Cam Software!!!

« on: February 02, 2011, 07:47:30 PM »

First of all let me start by saying this is my first post but I have been reading a lot of information posted here.  Thanks to everyones information I have completed building my cnc router and have it up and running without having to post anything new.  Currently I am using Alibre Design Expert and Alibre Cam Expert.  Unfortunately I found out earlier this week that Alibre doesn't import stl files thus making it impossible to open them in the cam window.  My original intent was to purchase Visualart from Mecsoft(already have visual turn and alibre cam) for creating the relief files for woodworking.  That's when I realized that I couldn't import stls.  Visualmill as a stand alone program will open these but since it is integrated in Alibre you are limited to the import options that it has.  I did find an stl import tool from Sycode that does work but the files that I plan to do will so large that it lags the software.  I am leaning towards Vectric Aspire and would like to have some input from people running this program already.  I have downloaded the demo and really like it so far but I know I have only brushed the surface.  One question I have is there a re-rough for 3d roughing?   I use this feature a lot at work with alibre cam as it drastically cuts the program size by only machining areas where the first pass tool was to large to fit in the smaller areas. Those that are using Aspire do you wish you would have went with something else?  I already have several thousand dollars tied up in software and I don't want to make the same mistake twice.  (should have purchased from Mecsoft instead of Alibre)   Any help would be greatly appreciated.