Messages

821

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 29, 2010, 01:27:40 PM »

Current Hi/low is an ouput signal that can be mapped to pin/port, look in config,pin/port,output.  BUT it signals on ANY axis movement and is WAY too far behind the data stream time wise.

I have seen this done from a motion card and a realtime system. I cannot fathom it working from mach(;-( WITHOUT the use of a macro. You would have to be able to TAP the function into the DRIVER level. AND as Art said once "That aint gonna happen".

I'm not familiar with the 'current hi/low', but my ignorance there is irrelevant since by your description, it would be unusable in any case. Sounds like you have a visual on the challenges.

In order to function, it seems to me that the trigger must come from the servo drive. So I would need a drive that has or will have some function that identifies a condition where the lock should be applied and released. Custom firmware is certainly one path. A 'position reached' function looks like a promising possibility.

Another poster mentioned the need to disable the drive while the spindle is locked. The 4th axis has a belt drive and the lock is on the spindle and *so far* there is enough 'give' in the belt that the drive is not too unhappy with a count of two off an 1800 line encoder . . . BUT . . I am also pursuing the solution mentioned where the drive is disabled during the lock event and re enabled. I am waiting to get one question answered by a vendor to determine the feasibility of that solution.

Overloaded: you are exactly correct.  Right now I have to manually insert the macros int the G-code. Automating that process would require messaging a post processor, as you correctly point out.  I want to avoid this. That is what drives the goal to make it automatic and transparent.

822

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 29, 2010, 01:13:05 PM »

I thought you had three modes:
1. Full A axis mode
2. Indexing mode
3. Spindle mode

I don't know where this came from, but it was not from me. I don't recall ever saying 'Full A axis mode' and I really don't even know what that would be.

There is no point in getting into a semantics argument.  There are no defined 'modes' so you can call them whatever you like, but there are only two. There is an A axis and a Spindle axis. One has postion and one does not. 

823

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 29, 2010, 11:15:17 AM »

Presumably you just want to look at the step/dir train incoming, unlock when it starts, and lock again when it stops.

Yes exactly, but only while in 'indexer' mode. In 'lathe' mode (including all simultaneous axis moves that include the 'A" axis), all locking would be disabled . .  except perhaps for an e-stop.

I guess what I would do is use an M-Code to close a relay that turns "indexing mode" on and off.  When its on, the locking is enabled and the lock synchronizer will function whenever it sees step pulses.  When off, the 4th axis stays unlocked for continuous machining.

Correct again. My thought is to rig two 'modes' for the locking function. When the 4th axis is in 'indexer' mode, the automatic locking feature would be active and in 'lathe' mode all locking would simply be disabled. This would be easy to trigger simultaneously with the swapaxis hardware. i.e. I could split the signal to the Swapaxis SELect pin and use a mirrored signal to enable the lock solenoid, or something like that.

It is an interesting challenge.

824

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 29, 2010, 10:59:03 AM »

2. Latency of the mechnanism. You will need to be able to "start" to deactivate the brake long BEFORE mach makes the actual move.

There is a signal mach has "current hi/low" that can trigger a relay on axis movement, we use it to drive the timer for the lube pumps,  BUT by the time the Brake reacts it it will be too late. Servo error or lost steps would be the results

Yet lateency is an issue, but only with unlocking. Right now I use macros to engage and disengage and I have delays built into the macros. A G4 command can also be used in the G-code immediately preceding the move.  My goals is to eliminate the need for manually inserting stuff into the G-code. To do that I need to find some available trigger that occurs at the correct point and use that to operate the lock.

What Mach signal are you using as a trigger?

825

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 29, 2010, 08:34:13 AM »

4th axis prototype is sold.

Currently I am working on making the 4th axis spindle lock function automatic and transparet to the CNC control so that a user does not need to manually addi macros to the G-code. There are a lot of ways to skin that cat and I would be interested to hear any ideas on how to accomplish that goal.

826

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 28, 2010, 06:57:13 PM »

4th axis prototype (previous model) for sale.

The new Super Duty prototype is finished and running, so I am finished with the previous prototype.  It is complete and working and ready to do 24/7 production work. I would rather see someone using it than to disassemble it for parts, so I have it for sale complete in the Bargain basement. I am only listing it in this forum initially.

The 3 Dugong drives are sold.

I am finishing modification to the new mil and some interesting new stuff will be coming soon on the new Super Duty 4th axis and 'semi-mini machining center'. Stay tuned.

827

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 27, 2010, 03:39:12 AM »

This is just a heads up for anyone seeking the currently backordered Dugong servo drives.

CNCdrive is making specially modified Dugong drives for my 4th axis project.

I have three brand new standard Dugong drives left that I will not be using and I have them for sale in the Bargain Basement here.

These are new and unused and CNCdrive is giving full new drive warranty to the buyer of these drives.

828

General Mach Discussion / Re: Aluminium Cutting

« on: April 25, 2010, 05:52:05 AM »

Katoh;

The solution to your dilemma is found in this old Vaudeville yarn;

Patient:  "Doc, it hurts when I do this!"

    Doc:  "Then don't do that!"

829

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 24, 2010, 09:09:52 AM »

Hobby users need BC as it provides an avenue for doing acceptable machining. I have seen some really crappy systems which use BC and do rather exceptional work.  

As always, you make good points.

I tried Mach's BC and found it to be useful only for spotting type functions . . drilling holes, etc.  The way it is implemented for continuous cutting, if I remember correctly (it's been quite some time) it actually stops with every direction change per axis. This is not useable in my opinion. I think there are solutions to this and I suggested a different approach, but the only result was to raise the ire of a couple of fanboys so it was not a topic that was interesting to discuss, but I'll be brave and just throw out another idea here.

If accuracy is the objective, then another way to spell BC is 'ground ball screw'. If you start with a smoothstepper budget of $180 (assuming $20 shipping . .LOL!) then you can find a pair of used ground ball screws on eBay and fit them to your machine and have money left over for a cold Bud lite. I think the worst used ballscrew will do a much better job than Mach's BC in it's current form.

My need is for a high pulse rate in order to get the RPM I need with the high count encoders that I also need, without resorting to step multipliers. That's a little more difficult to solve if you are going to stay with Mach3. I have quite a time investment in Mach3 at this point and there are a lot of them out there, so it's worth a bit more effort before turing off the porch light.

830

General Mach Discussion / Re: Aluminium Cutting

« on: April 24, 2010, 08:37:53 AM »

You are always going to be better off cutting all the way thru the material in one pass if you can, even if you need to use a slightly larger cutter. Likely marine grades of aluminum are called for here and those cut fairly clean. If I remeber correctly, the machine in question has enough power to make the 6mm cut.

The biggest issue in cutting aluminum in multiple dry passes is keeping the slot clear of chips, and heat generated at the bottom of the slot. Re-cutting chips also makes heat and lots of vibration, and the cutter rubbing on the sides of the slot make a lot of heat that cannot be carried away in the chip. A thru cut automatically clears the chips, runs cooler and smoother. In my experience, the clogging of multi flute cutters always starts at the bottom of a slot where the heat is highest. That's one reason a single point 'router' type bit is best to use as it only has a single contact point with the bottom of the slot. You can modify a normal cutter to resemble this profile by grinding the end to a concave shape, but better to spend the bucks and buy the excellent cutters produced specifically for this type of operation.

I'll just throw in a Simpson tip-of-the-week here for those who have 'tried everything' and still cannot get a multi pass cut to work for them. If you are having a bad time with a particular material, you can try offsetting each successive pass by say .003" to the climb milling side of the cut. The result is faily dramatic. There is a rather complicated explanation for this that I won't go into here, but I toss it out there as an option for those who are inclined to experiment.