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Kevin Ford Tue 06 May 2014 12:14

3D Subtractive Printing
11 Attachment(s)
The news is filled with 3D additive printers making awesome 4 cubic inch projects. Well we MechMate folks have been doing 3D subtractive printing for years, we just didn't know enough to call it that. There is also the minor difference is that our 3D print size is 4 x 8 ft. not 4 x 6 inches. Attached are a few examples made on our MechMate.

Some we made out of foam then used our home built vacuum molder to make additional copies or to strengthen the foam shape.

Sometimes we make a part out of MDF to be a mold, for example the attached dog potty drain pan.

darren salyer Tue 06 May 2014 12:59

Every time I see new things being made with a MM, I'm just blown away.
Brilliant use.

IMMark Tue 06 May 2014 16:19

Thanks for posting Kevin. I too have a vacuum former (and have lots of plans to use it along with the MM). I can't wait to actually make something!!

MetalHead Wed 07 May 2014 05:32

Sweet. Where did you get the plans for the vacuum former? Those are some cool projects.

Kevin Ford Wed 07 May 2014 09:42

Vacuum Former Plans
10 Attachment(s)
We built the Vacuum Former with plans from:

It was the best $65 I ever spent. Not only were the plans compete and accurate ut there were details for multiple options. It also included multiple sources of supply for parts, advice on buying used vacuum pumps and even a tutorial on how to use the thing when finished. He even supplies the hard to find heating elements and backing board.

Being able to make the forms on our MechMate then make multiple copies from sheet plastic is a real force multiplier.

Attached are a couple of pictures of our build.

The second to last picture is a 2ft x 2 ft drain pan moulded from 1/8th inch acrylic, including drain plug thread.

KenC Thu 08 May 2014 03:31


riesvantwisk Mon 12 May 2014 08:43

Kevin, thumbs up for using Pro Engineer

darren salyer Mon 12 May 2014 09:39

I've actually been looking at the same plans for a while now...

Kevin Ford Mon 12 May 2014 11:05

Hi Darren

If you have been looking at them then you will know the completeness of the Vacuum Former plans, (including details for building it in three sizes), right down to a bill of materials and multiple sources of supply. This documentation set let us get right to the building with little time spent filling in the details.

It was quite a contrast to how much time I spent researching, specifying and shopping around for electronics, motors and drives, etc. for our Mechmate project. I understand the differing philosophies on "guidance, but make it your own" vs "detailed specifications" in a project, but if I were to do it again, even though my son and I are Mechanical Engineers with strong electronics and software backgrounds, I would have preferred to start with a more complete reference design, that I could just build, or modify, if I felt the need.

That being said, I am in awe of the help freely given in the MechMate community and extremely grateful for the core instigators and maintainers of the community. However, I sometimes feel many of the questions on this site could have be pre-empted with a more complete starters package of drawing, schematics, electronics parts lists, etc. Maybe a couple of options for "low cost", "regular home garage" and "heavy production" sets of motors, drives and electronics might be the right balance of flexibility.

Then there is the CAD and G-Code generating software..... guidance on how to choose one over another and training specific to MechMate needs would be well received. I wasted more time and money in this arena that I want to admit and I am in the software business.

Given the total time and money I unknowingly committed at the start of my MechMate project, (building it is only the beginning), spending $50 to $100 up front on a more detailed design/build documentation set might have been the best investment I could make. It could be optional, just like the Laser Cutting starter packages.

The MechMate the community exists on the backs of a few, generously giving of their time and expertise. There are limits. I selfishly want these experts around for a long time. I suspect their time might be better spent and minimally compensated for by making an optional reference design kit.

I don't wish to appear ungrateful. If not for this community, I would not have a CNC machine in my garage. I just think that by taking some lessons from the Vacuum Molder documentation experience, we could encourage more folks to embark on a MechMate project, and more would complete the MechMate projects started, and in a shorter period of time, if they started with a more complete reference design. The knowledge is there, it just needs to be collected and organized. This in itself is no small task but we are 95% there now.

My main company writes mobile application software, so we are well aware of the issues in managing a project with multiple authors. These have all been flushed out by the Open Source Software development community. The experience and tools are transferable to a project like this. When the time is right, I could suggest a few free Open Source management packages to aid in collaborative authoring.


Alan_c Mon 12 May 2014 15:36

That option may well work in a well supplied market such as you are in, but remember this project originated in South Africa where the availability and supply of items differs vastly from your own or from someone in Aus, or Greece, or Malaysia or Brazil etc etc etc, and the methodology was established to make it possible for anybody in whatever location to successfully build and ultimately operate a fairly high tech piece of machinery

Those plans for the vacuum former which may be very good and complete, for you, are of little value to me who is nowhere near the sources listed and getting them here would be ridiculously expensive. The MechMate "format" while it may have some issues works well for most people throughout the world. For me building that vacuum former will require me to do a lot of searching, research and adapting to get it work, valuable skills I have honed while building my MechMate.

Kevin Ford Mon 12 May 2014 15:39

All valid points. Can there be no middle ground?

KenC Mon 12 May 2014 22:06

FOR Example, there are no way I can build the vacuum former economically with the BOM.... Hell I won't even know what heater to buy IF I don't research on the item...
P_s, If I were to purchase their kit, the heating element cost more than a water cooled spindle!!! Hence I said the vacuum former plan is a "temptation" but MM is definately "Do-able".

hennie Tue 13 May 2014 00:32

My Vacume forming Press that I use for the wrapped doors work on the same principle but on a big scale.The heater banks are items that can be bought at a good electrical shop valves comes from cobra that manufactures taps.and the rest is steel ,lights comes from a stove .This thing was built in South Africa so it can be done at good price.The pump though comes from Italy.I would say that in a radius of 20 km I would be able to source all my parts to build one.

KenC Tue 13 May 2014 00:48

Unless it is dedicated to a single region, its impossible to have "fits-all" BOM.
I'll wasted enough money on plans (with BOM) which I can never build within +/-50% cost variation over the decades...
Without a BOM, my MM are amongst the few economical builts known to the forum... :)

Kevin Ford Tue 13 May 2014 08:59

Hi Hennie
While mine can mold up to 2 ft x 4 ft and 1/4" thick PVC, one always wishes for a tool that is just a little bigger.
Pictures please!

hennie Wed 14 May 2014 00:22

Hi Kevin, I did a tread on the process it is somewhere in the forum I must say it was many moons ago.My table size is 9 x 4

Kevin Ford Wed 24 September 2014 04:12

Hi Hennie
I am ashamed to admit I could not find that thread. Can you point me to it?

ittichai Fri 09 October 2015 04:08


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