Reply with QuoteNo, I don't think a fixed gantry can be too heavy. Mine is 12x12x1/2'' wall square steel tube. More mass is good.
Looking for input on machine ideas.
I've been in the planning/idea stage for a while now on a DIY router table. At this point I have nothing sketched out but thoughts are for a fixed gantry router table. I initially wanted to build a roughly 2x3 foot cutting area router. I came into the option to purchase a pick and place robot at a really great price. I chose it specifically for the linear rails and assorted other useful parts (emergency shutoff, cable drag chains, tons of air lines). At this time my questions are primarily on the fixed gantry and associated moving table. Pros/Cons? Can the fixed gantry be too large? Here are some pictures of the pick and place (what's left) The top has been milled and the rails are flat. If I narrow this down (including the rails) would these be suitable for the gantry?I had planned to use ballscrews throughout but also wanted opinions on belt drive or R&P for the X axis. Thanks for the input, I appreciate any guidance, suggestions or opinions.
Video here running indicator over rail.
https://drive.google.com/file/d/1_NM...ew?usp=sharing
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Re: Looking for input on machine ideas.
No, I don't think a fixed gantry can be too heavy. Mine is 12x12x1/2'' wall square steel tube. More mass is good.
Re: Looking for input on machine ideas.
Thank you for the reply Jim. How large is your gantry and table? How do you drive your X axis? I initially planned to use ballscrew but with the beam being closed thought something else might work better. I'm assuming you have a fixed gantry as well. Definitely doesn't seem to be the norm.
Re: Looking for input on machine ideas.
My work area is 4' x 8' x 12''. Yes, my gantry is fixed. All axis are ball screws. I'm driving them with NEMA 34, 1200 in/oz steppers. The table is 1 inch thick aluminum tooling plate, with 3/4 inch thick Delrin over. I'll be happy try to answer any other questions you have.
Here is the best picture I have of it to give a general overview, unloading to move into my shop. It's about an inch off of the trailer in this pic.
Re: Looking for input on machine ideas.
To answer the question first posted. It is really hard for a fiexed gantry to be too large. What stops most people is economics that is the cost of the gantry blows the budget before diminishing returns on structural issues happens. Excessive length can be a problem but also an advantage, a long gantry for example gives you a place to do tool changes.
As you already know the pick and place units, sometimes called extractors on injection molding machines, can have many savagable parts including a gantry beam. Sadly many are shot to hell when removed from a plant, sometimes you get lucky. In any event these units are often very cost effective sources for used parts that people might not be aware of.
Wow! Nice machine. Who was the builder? In many ways this is close to what was once called a planer mill. The big difference on planer mill is that the gantry would move up and down on the columns.Originally Posted by Jim Dawson
My work area is 4' x 8' x 12''. Yes, my gantry is fixed. All axis are ball screws. I'm driving them with NEMA 34, 1200 in/oz steppers. The table is 1 inch thick aluminum tooling plate, with 3/4 inch thick Delrin over. I'll be happy try to answer any other questions you have.
Here is the best picture I have of it to give a general overview, unloading to move into my shop. It's about an inch off of the trailer in this pic.
Re: Looking for input on machine ideas.
That is a Thermwood. Not sure when it was built, 80's maybe. It is somewhat similar to a planer mill, but a lot lighter. This router only weighs about 5000 lbs, but it is solid.
Here is a 36x96 planer mill that was converted to a CNC in a shop I used to work for, I never did have a need to use it. Sorry for the crappy picture.
Re: Looking for input on machine ideas.
The linear slides on the pick and place were in great shape and reason alone to buy it for the price I did. One rail had some rust but it seems to have cleaned up with only staining left behind. I salvaged a lot of air line pieces and parts and the electronics that Im not planning to use on my router. I want a full 5' cutting width on gantry. Figure belt is a no go due to length. Little unsure of how to design a R&P drive and secure the rack with the gantry beam being enclosed. Any thoughts on chain drive? Too inaccurate? Any input is always appreciated.
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Re: Looking for input on machine ideas.
They do make rack that is already tapped and counterbored. One idea would be to run the rack on the top of the gantry beam, which I've seen on many a DIY build. Ballscrew would work if you can find block style bearing units that will fit between the LM blocks. Or, you could reuse those plates at the ends of the gantry, and cut holes to accept flange style bearing units.
