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Messages - John Mac

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1
General Mach Discussion / Re: Mach 3 Sewing Machine
« on: May 02, 2019, 10:03:28 AM »
Hi All

Here may be the answer to all those wanting to build any sort of CNC sewing machine!

The program path needs to be reversible because the thread often breaks when stitching requiring the machine to be backed up to before the break, then rethreaded. and finally restarted, overlapping the end of the first run in the trade called "back tacking" and the restart.

The controller needs to reverse, and this one can! I am sure the 35000 program segments will be more than enough to do this sewing paths are very simple. It needs to be a simple push button function with the path reversal shown on the Display screen.

Thanks to the post below this may be the solution.

I stumbled across the You tube Channel "Applied Science".
https://www.youtube.com/watch?v=rpHYBz7ToII
The post describes Building an EDM Drill.... quite interesting, however I do not wish to build one.
However the builder just happened to mention that the CNC controller he used was able to feed in reverse back up the program buffer as well as forward. I nearly fell of my chair!

So I emailed the KFLOP company and promptly got the following response.

Quote
Yes our KFLOP Controller has the ability to perform hardware feed rate override (FRO) including negative feedrates.  See here.  KFLOP has a motion buffer that can contain up to 35,000 coordinated motion segments.  This is typically many seconds of motion depending on the complexity of the path and speeds.  So it is possible to reverse this amount of motion.  When using Feed Hold in our KMotionCNC program two buttons (Forward/Reverse) are enabled which are coded to command the Feedrate to +0.2 and -0.2.  See this video. the important bit is towards the end.

https://www.youtube.com/watch?v=uPQfGeydsDM

As far as I know Mach can not do this? Can anyone confirm?

End Quote

Regards
John

2
Show"N"Tell ( Your Machines) / Re: DIY Epoxy Frame based CNC MILL
« on: March 23, 2019, 07:48:15 AM »
Hi All

Some good progress. The Saddle and the Z Axis has been cast and machined.

http://www.mediafire.com/file/ouxan7gqp9upapg/O1_Saddle_23-03-2019_6-43-15_PM.jpg/file

More photos at my blog here.
https://www.model-engineer.co.uk/forums/postings.asp?th=139042&p=3

Regards
John

3
General Mach Discussion / Re: quilting or embroidery machine
« on: March 19, 2019, 08:51:46 AM »
Hi
I have attached a photo of a RESTA H220 control panel

As you can see it is written in Italian however it is easy to translate. The section marked Automatico is for downloading programs from the control system. You can ignore that section as it would be covered by Mach3 or 4

The section marked Semiautomatico contains buttons that allow you to move forward = Avanti, backwards = indertro, along the stitch line.
The repositionmento button allows you to move to the last known position where the the machine stopped within a running program, not after a reset.

The red buttons are just lights.

This system was developed over 20 years ago. However it has great functionality from an operators perspective.

See my earlier comments in this post for a fuller description.

Regards
John

   



4
Mach4 General Discussion / Re: pay for help
« on: March 07, 2019, 10:45:59 PM »
From memory Delta Tau was taken over by Omron.
I am surprised they have left you stranded.
Have you talked to Omron directly?

Regards
John

5
Show"N"Tell ( Your Machines) / Re: DIY Epoxy Frame based CNC MILL
« on: March 01, 2019, 10:13:25 PM »

6
Video P*r*o*b*i*n*g / Re: 3d Probing on Granite slabs
« on: February 26, 2019, 05:01:00 PM »
Hi

Google high precision micro switch
https://www.google.com/search?q=high+precision+micro+switch&rlz=1C1ASUT_enAU791AU791&oq=high+precision+micro+switch&aqs=chrome..69i57.12774j0j8&sourceid=chrome&ie=UTF-8

Omron have a good range
https://www.google.com/search?q=high+precision+micro+switch&rlz=1C1ASUT_enAU791AU791&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj2wPHTsdrgAhVYb30KHV2QAjIQ_AUIDigB&biw=1174&bih=493#imgrc=e3unll0hLvCuPM:

If there is a risk of over travel damaging the switch place it in a spring loaded plunger that will allow it to move up and protect it from damage.

For the resolution you need it should cost less than $100

Regards
John

7
Show"N"Tell ( Your Machines) / Re: DIY Epoxy Frame based CNC MILL
« on: February 12, 2019, 07:41:55 AM »
Hi All

Assembly of some of the laser cut parts, also some machining done.

Write up here:
https://www.model-engineer.co.uk/for...?th=139042&p=3



Regards
John

8
Show"N"Tell ( Your Machines) / Re: DIY Epoxy Frame based CNC MILL
« on: February 07, 2019, 09:19:08 AM »
Hi All

At last the 4 main castings have been test assembled.
Had I not used laser cut molds I don,t think I could have achieved the level of accuracy obtained.


There s a full write up here:
https://www.model-engineer.co.uk/forums/postings.asp?th=139042&p=3

Regards
John

10
Show"N"Tell ( Your Machines) / Re: DIY Epoxy Frame based CNC MILL
« on: January 24, 2019, 10:12:15 PM »
Hi Bird

Hopefully the base will be poured soon, We have had 40c deg heat this week pretty warm! So the pour was put off.
As soon as that is done the Z axis and carriage will be next. I will document it soon.

Tip.

If you are using linear rails and ball screws, make a definite decision on those first. When choosing ball screw end bearings for a given ball screw there will likely be two different sizes that will fit, Choose the larger size for extra stiffness. If you are not making your own there are also various ballnut mounts available, some steel some aluminium, I choose steel.

I am guessing you are finding that when you add up all the heights of the x axis bearing rails and slider blocks, the ball screw end bearings and ball nut mounts and allow for fastenings you end up with a height problem. The setup does not work well with simple plates unless you stack in spacer plates. One option is to machine the plates from solid if you have the facilities. The design I am working on uses a hybrid of laser cut steel plates, turned pillars and is epoxy filled. Oh! and the carriage is heavy.

If you like post a screenshot of your current design. Everyone faces this problem and it would be interesting to see different approaches.

Regards
John

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