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firebrick43
Sat 19 January 2008, 19:32
Hello all,
I have spent alot of time looking and lurking, reading thru most of the post, learning as much as I can. Anyways, there is alot I like about the MechMate, especially it robustness that is missing from the sub 25000 dollar machines out there. I really need to do UHMW and HDPE plastics and light aluminum for a bussiness endevor and plywood only for hobby work. If I remember correctly, I read that Gerald stated if a customer came wanting to have these materials cut that he would send them to a competitor and they would send him MDF work. But it wasn't really explained why? Are these machines still not stiff enough? Maybe a different spindle would be an advantage? Surface finish bad? I have the facilities and tools to build this if it will work out better than systems such as the torchmate and similar lightly built gantrys originally designed for plasma/oxy cutting apps.

Thank You

Gerald D
Sat 19 January 2008, 20:51
It is the surface finish that is the main issue with a "budget" machine, and we have face facts that the MechMate is a budget machine.

firebrick43
Sun 20 January 2008, 00:18
Gerald, I would not sell yourself or the mechmate short by calling it a "budget machine" I have heard my father say many time that there is three ways to do anything. Fast, inexpensively, or high quality. You can have any two of the three but you have to choose which two.

You have a very robust and well thought out frame design the out does all of the competition in machine 3 to 4 times as much. My guess that it was surface finish and after spending another couple of hours reading back post I cam across this statement you made.

"Realizing that we have direct drive motors, the general client feedback is that they are happy with MDF and softwood cut for them, but that they want better for acrylic plastic (perspex). If we had gearboxes, we could probably also satisfy the plastics guys."'

So it is my understanding that you feel that the surface finish is not do to harmonics, runout in the spindle motor,frame occilation/movement, or rail/bearing systems. But in stepper motor resolution.

I would happily pay for gear boxes to improve resolution even at the cost of speed or budgetary concerns

Gerald D
Sun 20 January 2008, 08:22
Jay, we received our first set of geared motors last week and we are interested to see what the difference in cut quality is going to be.

I don't have a commercial agenda and therefore do not try and promote the MechMate for anything that I am not experienced with, and know for an absolute fact that it will do. We did experiment a bit with plastics, but for many reasons we decided the money was not there. The issues from memory:
- Couldn't develop a feel for the correct spindle and moving speeds. Melting plastic was a devil. (we only had a router then)
- Couldn't tell one type of plastic from the next. A customer brings a sheet of plastic and didn't know what it was, except that it was expensive.
- Sheets arrived with scratches, but the customer blamed us for them.
- The static electricity made the chips stick everywhere.

We developed a very happy relationship with a guy who loved cutting plastic on his Multicam, and he hated wood. (his wood customers would complain that he embedded alu chips in the wood, or left kerosene stains).

So, I have just adopted the easy stance - if someone asks if the MechMate is okay for plastic & alu, I say "no". I have no reason to say "yes". If a couple of guys start raving about how well their MM's cut plastic and alu, then I could start offering a qualified "yes". (There are a very small number of guys happy that their ShopBots cut plastics and alu - the MM should top that)

PS. Our plastics experience was with original gantry/car shopbot 3 years ago - since the beefed-up MM conversion, plus the spindle, there has been no serious attempt at plastic again.

firebrick43
Sun 20 January 2008, 15:01
Thank you Gerald,
Rare to see someone as honest, truthful, and humble as you are.