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I have a discussing going on with @spenca on welded lathe bed design, and I thought some of y'all would be interested in this information:
If I was going to weld up a lathe bed, I would start with some box tubing or pipe and weld the ways on top of it. I would heat the whole thing before I started welding to minimize the distortion; 100C is more than enough to make a big difference. Heat treatment after welding isn't likely to be a big win; doing it right is going to be quite hard; you need the temperature pretty uniform and smooth ramp up and down. And you don't actually want to anneal it, as that will destroy the strength of your steel.
After it was welded I would take another box tube that fit inside the main tube and glue/bond rubber all the way around the outside of it. Slide it inside the first tube and then inject epoxy (ideally steel or iron filled) into the space between them. This will give you a structure with MUCH more damping than you would get with steel, and also much more than a sand fill would give you.
This book DOES discuss weldments for machines: Design of Weldments by Omer W. Blodgett. Search for a PDF of it... Page 1.5-8 discusses converting a lathe base casting into a weldment.
Section 3.3 covers "Designing for Improved Vibration Control"
Section 4.1 is "How to Design Machine Bases"
This PhD thesis is REALLY great:
https://my.mech.utah.edu/~bamberg/r...Design/Principles of Rapid Machine Design.pdf
Page 94 starts discussing what I mentioned above on the constrained layer damping
Page 110 shows actual fabrication!
From Bamberg:
I've attached actual time response data for undamped, sand filled, concrete filled, and constrained layer damping. Fascinating!
The rubber wrapped reinforced concrete damper was jaw-droppingly effective. 0.3 loss factor is "thud", not "ring".
He took a steel pipe (might be 5") and put four rubber tubes (made from sheet damping material) into it, with a 2" pipe core to keep concrete out of the middle. Each tube got three rebar sections. The space was filled with concrete dosed with an agent to make it expand a little bit on setting. Here's the end with some sealing blocks in place.
Testing looks like this. This also has a good view of the finished and trimmed beam.
From Blodgett:
If I was going to weld up a lathe bed, I would start with some box tubing or pipe and weld the ways on top of it. I would heat the whole thing before I started welding to minimize the distortion; 100C is more than enough to make a big difference. Heat treatment after welding isn't likely to be a big win; doing it right is going to be quite hard; you need the temperature pretty uniform and smooth ramp up and down. And you don't actually want to anneal it, as that will destroy the strength of your steel.
After it was welded I would take another box tube that fit inside the main tube and glue/bond rubber all the way around the outside of it. Slide it inside the first tube and then inject epoxy (ideally steel or iron filled) into the space between them. This will give you a structure with MUCH more damping than you would get with steel, and also much more than a sand fill would give you.
This book DOES discuss weldments for machines: Design of Weldments by Omer W. Blodgett. Search for a PDF of it... Page 1.5-8 discusses converting a lathe base casting into a weldment.
Section 3.3 covers "Designing for Improved Vibration Control"
Section 4.1 is "How to Design Machine Bases"
This PhD thesis is REALLY great:
https://my.mech.utah.edu/~bamberg/r...Design/Principles of Rapid Machine Design.pdf
Page 94 starts discussing what I mentioned above on the constrained layer damping
Page 110 shows actual fabrication!
From Bamberg:
I've attached actual time response data for undamped, sand filled, concrete filled, and constrained layer damping. Fascinating!
The rubber wrapped reinforced concrete damper was jaw-droppingly effective. 0.3 loss factor is "thud", not "ring".
He took a steel pipe (might be 5") and put four rubber tubes (made from sheet damping material) into it, with a 2" pipe core to keep concrete out of the middle. Each tube got three rebar sections. The space was filled with concrete dosed with an agent to make it expand a little bit on setting. Here's the end with some sealing blocks in place.
Testing looks like this. This also has a good view of the finished and trimmed beam.
From Blodgett: