I'm actuating a tilting bandsaw with a foot pedal. It must go in both directions. I am considering using one or two sewing machine motors and foot pedals. Also I'm considering using a Arduino with a stepper motor, and a Pot foot pedal. These are the best ideas that I've come up with. But I'm sure there might be a few options I haven't considered. Feel free to one word in! Thanks. Happy Botting.
Jeff in Van Nuys, CA
Building an Actuated Bandsaw....
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Bot Master Spin
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Re: Building an Actuated Bandsaw....
By tilting do you mean right-left or up-down? My answer is tilted toward up down and parts of it might not be useful if you mean right left.
As far as I know, all sewing machine motors are one direction however with a footpedal it's inherently variable speed. With a clutch and a return spring to move the saw back up it seems like a simpler solution.
Using a stepper and a digital controller (Arduino) would give you more flexibility but at a cost of complexity. The stepper can be run in both directions providing you have a foot pedal that supports two directions or can null the pot in the center. This system could also be wired into any number of cutout and kill switches to make it safer.
Naturally all sorts of safety questions come to mind like what happens when you step on the pedal while your arm is under the saw ert. I'll leave that up to you but if this is intended to be used by anyone other than yourself, you need to consider that carefully or buy an umberella insurance policy to protect you from possible product liability or neglegence suits.
If you do mean right left tilt, then the stepper solution is the way to go. This even lets you preprogram set points and digital angle display.
As far as I know, all sewing machine motors are one direction however with a footpedal it's inherently variable speed. With a clutch and a return spring to move the saw back up it seems like a simpler solution.
Using a stepper and a digital controller (Arduino) would give you more flexibility but at a cost of complexity. The stepper can be run in both directions providing you have a foot pedal that supports two directions or can null the pot in the center. This system could also be wired into any number of cutout and kill switches to make it safer.
Naturally all sorts of safety questions come to mind like what happens when you step on the pedal while your arm is under the saw ert. I'll leave that up to you but if this is intended to be used by anyone other than yourself, you need to consider that carefully or buy an umberella insurance policy to protect you from possible product liability or neglegence suits.
If you do mean right left tilt, then the stepper solution is the way to go. This even lets you preprogram set points and digital angle display.
Re: Building an Actuated Bandsaw....
I know this is an 'electronics forum' but I would seriously consider using pneumatics! Speed, and position control are easy. Use either a 4 way solenoid or a manual foot or hand valve. With a double acting cylinder both up/down actons would be mechanically simple to incorporate. Pressure and flow restrictor valves alter the force applied and the ram's speed. A sewing machine motor is high speed and low torque so some gearing would be required. Ditto for the stepper!
Hacker note: Pneumatic cylinders are available with magnetic switches and potentiometers to sense the piston's position. Use a micro to control the cylinder's solenoid valve with the sensor feedback if you need more bells and whistles!
More economy? Use the cylinder exhaust air to blow away chips! 
Side note: A double acting cylinder will produce slightly more ram pressure on the push stroke than the retract stroke for the same applied pressure!
Len
Hacker note: Pneumatic cylinders are available with magnetic switches and potentiometers to sense the piston's position. Use a micro to control the cylinder's solenoid valve with the sensor feedback if you need more bells and whistles!
More economy? Use the cylinder exhaust air to blow away chips! Side note: A double acting cylinder will produce slightly more ram pressure on the push stroke than the retract stroke for the same applied pressure!
Len
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
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Bot Master Spin
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Re: Building an Actuated Bandsaw....
Ok, so more specifics were needed. I am actuating the tilt so that while cutting a board the operator can tilt and straighten while cutting. The parts being cut are for use in boat making. So that the alternating angles match up on a curved hull. It will only be used by one fabricator so safety will be up to the operator. And I was planning on using kill switches, and most likely an emergency shutoff. I am assuming that the tilt mechanism is screw actuated so hooking up a stepper should be fairly easy in terms of the mechanics of the device.
I did not think of Pneumatics, but that does sound like a great use. I have used steppers before to convert a lathe to be cnc, so using an arduino would be a piece of cake in comparison to an arduino. I think that the pnuematics will be a great thing for me to learn but I have limited experience with them. Are there any suppliers for pnuematic actuators and solenoids that you might recommend? What sizes would I want to consider? How are they sold? Thanks for the advice I sincerly appreciate all of your input.... (I just bought a CNC Machining center so let me know if you need some parts?)
Jeff
I did not think of Pneumatics, but that does sound like a great use. I have used steppers before to convert a lathe to be cnc, so using an arduino would be a piece of cake in comparison to an arduino. I think that the pnuematics will be a great thing for me to learn but I have limited experience with them. Are there any suppliers for pnuematic actuators and solenoids that you might recommend? What sizes would I want to consider? How are they sold? Thanks for the advice I sincerly appreciate all of your input.... (I just bought a CNC Machining center so let me know if you need some parts?)
Jeff
Re: Building an Actuated Bandsaw....
Jeff,
Pneumatics are really fairly simple. The hardware is readily available from places like Grainger, McMaster Carr and MSC as well as local suppliers.
General Info!
Actuators, or cylinders, are available as single acting, which use pressure to extend and another means, like a spring, to retract. Double acting cylinders require air to move in either extend or retract. Cylinders are available in bores and strokes from less than 1 to 12+ inches with a multitude of mounting options and add-on features like position switches and feedback potentiometers. The extend ram force is calculated by multiplying the piston face area in square inches by the applied pressure in psi. A piston 2" diameter =3.14 sq inches piston face X100psi=314 pounds of ram pressure. For retract force, calculate the area of the ram and deduct it from the area of the piston face before multiplying
A cylinder must be exhausted before it can move again so all controls must include exhaust valving
Valves can be 3 way (think SPDT switch) or 4 way (think DPDT wired to reverse DC polarity) and are generally available in many manual and solenoid designs with different coil voltages. There are manifolded valves that mount together to share a common air supply for compact multi-valve designs
All valves have, as a minimum, a supply, exhaust and one or more output ports.
Tubing and fitting sizes are from fractions of an inch and up, depending on the air volume required to operate the cylinder at the desired speed. There are restrictors, check valves, flow controls, regulators, filters, oilers, silencers and many other accessories to make a long lasting work horse system. Grainger sells most of these items as well as an excellent manual (Stock #5H566) by Parker for pneumatic control theory and design, about $30. Do check local Parker dealers, their pricing could be less!
Need more info, just ask!
Len
Pneumatics are really fairly simple. The hardware is readily available from places like Grainger, McMaster Carr and MSC as well as local suppliers.
General Info!
Actuators, or cylinders, are available as single acting, which use pressure to extend and another means, like a spring, to retract. Double acting cylinders require air to move in either extend or retract. Cylinders are available in bores and strokes from less than 1 to 12+ inches with a multitude of mounting options and add-on features like position switches and feedback potentiometers. The extend ram force is calculated by multiplying the piston face area in square inches by the applied pressure in psi. A piston 2" diameter =3.14 sq inches piston face X100psi=314 pounds of ram pressure. For retract force, calculate the area of the ram and deduct it from the area of the piston face before multiplying
A cylinder must be exhausted before it can move again so all controls must include exhaust valving
Valves can be 3 way (think SPDT switch) or 4 way (think DPDT wired to reverse DC polarity) and are generally available in many manual and solenoid designs with different coil voltages. There are manifolded valves that mount together to share a common air supply for compact multi-valve designs
All valves have, as a minimum, a supply, exhaust and one or more output ports.
Tubing and fitting sizes are from fractions of an inch and up, depending on the air volume required to operate the cylinder at the desired speed. There are restrictors, check valves, flow controls, regulators, filters, oilers, silencers and many other accessories to make a long lasting work horse system. Grainger sells most of these items as well as an excellent manual (Stock #5H566) by Parker for pneumatic control theory and design, about $30. Do check local Parker dealers, their pricing could be less!
Need more info, just ask!
Len
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
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Engineer1138
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Re: Building an Actuated Bandsaw....
For safety's sake I wouldn't use a foot pedal. I'd rather have dual pushbuttons separated by at least 2' so I could be reasonably sure that the operator's hands were clear of the saw before it was powered on.
Don't forget that your Panic switch should be big, red, and have no electronics associated with it: just shut the power off when it's hit.
Don't forget that your Panic switch should be big, red, and have no electronics associated with it: just shut the power off when it's hit.
Re: Building an Actuated Bandsaw....
Pneumatics are too springy for precise work. The air can expand and compress. But hydraulics would work. Just drain the air and fill with oil.
I'd go with the stepper controlled threaded rod.
I'd go with the stepper controlled threaded rod.
-=VA7KOR=- My solar system includes Pluto.
Re: Building an Actuated Bandsaw....
check out cnc zone and search for a cpld stepper controller by mariss $1.00 cpld and a h bridge,
sine cos quiet pwm, by far the best open source controller.
Amplexus
sine cos quiet pwm, by far the best open source controller.
Amplexus
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