Topics

11

Show"N"Tell ( What you have made with your CNC machine.) / My latest longer term project

« on: December 10, 2012, 03:16:30 AM »

Hi,
This is part of my latest home designed project.  I hope the final assembly works as designed.

Machined from Aluminium in my Syil X3 Mill using Mach3, then faced off from the reverse side to final thickness in my manual mill.
 
Regards

Chrisjh

12

*****VIDEOS***** / Using HSMXpress Adaptive Clearing

« on: December 10, 2012, 02:36:43 AM »

Hi,

Been some time since I posted.  I recently downloaded and integrated the free HSMXpress CAM program into my copy of Solidworks.  What a step up from my previous methods!!  I am impressed.

This video shows the machining (adaptive clearing) of a 38 x 38 mm Aluminium Lid for a 4 cavity microwave filter.  Details of the cutter and feeds and speeds are described in the text for the video.

I also machined the associated 4 cavity filter, something my previous methods would taken aged to program. 

The video is not very impressive, but gives some idea of the adaptive clearing capability of HSMXpress.  The on-line youtube tutorials are great.

http://www.youtube.com/watch?v=Dku0SqnpOGA&feature=youtu.be

Happy viewing.

Chrisjh

13

Show"N"Tell ( What you have made with your CNC machine.) / Manufacturing SMA Female Open for VNA Calibration Kits - Video

« on: May 16, 2012, 06:23:53 PM »

Hi,

Its been a while since I posted so here is the latest.

Enjoy!!

http://www.youtube.com/watch?v=qeS-fteX7DM&feature=youtu.be

Regards

Chrisjh

14

G-Code, CAD, and CAM discussions / Example of using the L Repeat and Incrementing Z movement

« on: February 16, 2012, 06:10:24 AM »

Hi,

I am trying to hand code a facemill operation that involves repeating the same facing movements 5 times at increasing depth of 0.5mm, starting with the first cut 0.5mm deep.

Can someone give me an example of how you would code this using the "L word" number of repeats?

I have some code to cut at Z-0.5 and just want to generate a clever way to get to the final cut without having to repeat the code 5 times at the incremental depths.

Regards

Chrisjh

15

G-Code, CAD, and CAM discussions / G96/G97 Command Structure

« on: October 17, 2011, 06:41:35 PM »

Hi,

I have been having random results with my G96 (CSS) and G97 (RPM Mode) calls.  I use mixed CSS and RPM routines in my programs.  Sometimes it works well as programmed and sometimes it drives me nuts.  The symptoms vary but, as an example, when I switch from CSS mode to RPM mode, the spindle will run at either max or min RPM and nothing will fix it.  The general fix has been to shutdown everything and start again.

Yesterday I stumbled on the Startup Modals Check Box" Use Init string on ALL resets" for Initialization Strings and setting the string to contain "G97 S500" helped to get Mach3 out of CSS mode without shutting down.

I carried out further investigations of the structure of the G96/G97 commands in Smid's CNC Programming Handbook and on the Internet in general.  Smid's G96 example is structured G96 S45 M03 and G97 S500 M03.  Programming like this seems to have fixed my lathe's random behaviours.  My coding included the M03 (or M04) command for the first G96 call but I had assumed that the M03 was modal and subsequent M03 commands were not necessary in C97 CSS cancellations.  It appears not to be case.

I have tried to find out why the inclusion of the Spindle On (M03 or M04) in G96 and G97 calls appear to be mandatory but with out absolute clarity.

Can anyone confirm my suspicions regarding the necessity to include a Spindle On command with every G96 and G97 block?

Regards

Chrisjh

16

Show"N"Tell ( Your Machines) / How I solved my Stepper Motor Resonance Problem - Video

« on: August 25, 2011, 12:20:13 AM »

I have had a terrible problem with bad resonance with the Z Axis on my CNC Lathe.  The problem only appeared at certain feed rates.  The lathe has smooth operation at most feed rates.

In desperation, I had to try to program around the feed rate that I wanted to use (0.25mm/rev) to avoid the resonance; as it was affecting the quality of turned parts. I.e. I would use a non-ideal 0.15 or 0.35mm/rev to avoid the problem.

I tried all the advice that I could find on the internet to no avail. I even changed the Stepper Motor and Stepper Motor Drivers to a different makes.  No luck.  I tried varying the Power Supply Voltage to the Driver with absolutely no effect.

I then tried a mechanical approach by adding a flywheel to the Z Axis Stepper Motor.  Bingo!!!  Why didn't I do this 3 years ago?  So simple and so effective!!!

The video shows a wobble in the flywheel which resulted from my poor hand tapping skills.  I will make a new flywheel when time permits; now that I seem to have the problem licked.

The flywheel is Ø99 x 14 thick and made from mild steel.  There was absolutely no maths used; rather a simple application of the laws of physics and gut feel!!!

See video here  http://www.youtube.com/watch?v=mqCL7g4gwAU

Regards

Chrisjh

17

Show"N"Tell ( What you have made with your CNC machine.) / Using Biodiesel as a machining fliud - Video

« on: August 16, 2011, 01:27:03 AM »

I have been using biodiesel for some time now on my CNC lathe. The water soluble coolant that I used previously was causing problems with the linear bearings seizing (presumably from oxidation) following periods of inactivity.

I know of a professional CNC turning company that uses oil that looks like, and has the consistence of honey, so decided to abandon water based coolant for an oil based solution. The cost of such oil coolant is prohibitive so I decided to use biodiesel. This worked fine but left a sticky residue. I now dilute the biodiesel with ordinary diesel (ratio 3 parts biodiesel to 1 part diesel). This leaves no sticky residue and the machine is now very clean.

Biodiesel has a high flash point (higher than ordinary diesel) and has excellent lubrication properties.

The part being machined in the video is part of an oil filter adaptor I manufacture.  I had some 32mm threaded adaptors which were not popular so I decided to re-machine them to 27mm thread.

The material being cut is 12L14 steel and DOC during roughing is 0.4mm at a feedrate of 0.25mm/rev. The finish cut is done at 0.1mm/rev. Threading is done at 900rpm.
 
I also mix biodiesel with kerosene for manual applications with a squirt bottle on my manual lathe and milling machine. I also use raw biodiesel as a hand tapping lubricant (works great).

See video here  http://www.youtube.com/watch?v=jxEk4o5OLT4

Regards

Chrisjh

18

G-Code, CAD, and CAM discussions / G41 Offset being ignored

« on: October 08, 2010, 09:10:19 PM »

The G Code in the attachment below ignores my G41 Offset Lines.

What am I doing wrong?

There is a reason I am using the subroutine.  I have 3 other similar programs with multiple identical holes and using subroutines is the most compact and efficient way.

If I can get this simple one hole version going, I can then fix all programs and learn by my mistakes.

Regards

Chrisjh

19

G-Code, CAD, and CAM discussions / Cutter Offset Learning Problem

« on: September 27, 2010, 10:23:09 PM »

Hi,

I am trying for the first time, to program my mill using cutter compensation but with no success.

Wizard generated code for circular items (both internal and external) work fine with "Px" cutter offsets.

When I add a "P6" to my own programs with G41 offsets, I get large 360 degree arcs at the 0.2mm radii on the corners.

Attached are 2 files. The first one results in correct toolpath (without cutter compensation) and the second file with added "P6" to the G41 lines results in the circular arcs at the 0.2mm radius corners.

What am I doing wrong?

I am using Version R3.042.040.

Regards

Chrisjh

20

Show"N"Tell ( What you have made with your CNC machine.) / Guess what these are used for

« on: September 18, 2010, 12:16:24 AM »

Hi All,
You will never guess what there are.  My son asked me to make 50 following a trial of 10 made recently.
 
Made in two parts and screwed together.  I didn't have a suitable 5C Collet for the 3/8” square part so I made a round collet that was a slip fit across the corners of the square bar and them cross drilled and tapped it M6.
 
Both parts made in my cnc lathe.  Threading was done manually. Material is aluminium which I chromate converted at the end.
I am not 100% sure how they are used myself.
Chrisjh