I wanted to post a thread about linear stepper motors in the proper section of this forum to see how we could make these more affordable. They are very expensive; for example, a basic single axis linear stepper from H2W is $855 for a forcer, and $2,225 for a 48 in. long platen.
The platen is a piece of precision ground steel bar stock, and can be found at McMaster-Carr in lengths of 1.5 ft., 3 ft., and 6 ft. which is great. The bar stock isn't too badly priced. [www.mcmaster.com]
The platen needs teeth cut into it at a tooth pitch of 1mm, teeth width of 0.5mm, and a cut depth of 0.5mm.
I think the platen could easily be made at home with a wet tile saw and a jig. The jig would be a sled that places the bar stock at the proper cutting depth from the arc of the blade, and the jig will have a pin that sets the pitch of the teeth; for each cut made the previous tooth is placed over the pin in the jig.
The platen is the method of movement, the linear guide, and could also be used as the towers in a delta printer directly, making for a sweet setup.
The forcer will be more complicated to make; it is essentially a transformer split in half with a permanent magnet between the two and ball bearings that ride along the platen. The force of the permanent magnet means you can use the linear stepper in either a horizontal or vertical position. The ball bearings maintain a 25 micron air gap between platen and forcer.
Someone in another thread mentioned the moving wires in the forcer and that it would be better if the electromagnets were in the platen. While this is possible, it isn't feasible or cost effective to build in a multitude of electromagnets within the length of the platen as more machining would be involved.
Everything you could ever want to know about linear stepper motor theory and design is in this publication: [issuu.com]
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The platen is a piece of precision ground steel bar stock, and can be found at McMaster-Carr in lengths of 1.5 ft., 3 ft., and 6 ft. which is great. The bar stock isn't too badly priced. [www.mcmaster.com]
The platen needs teeth cut into it at a tooth pitch of 1mm, teeth width of 0.5mm, and a cut depth of 0.5mm.
I think the platen could easily be made at home with a wet tile saw and a jig. The jig would be a sled that places the bar stock at the proper cutting depth from the arc of the blade, and the jig will have a pin that sets the pitch of the teeth; for each cut made the previous tooth is placed over the pin in the jig.
The platen is the method of movement, the linear guide, and could also be used as the towers in a delta printer directly, making for a sweet setup.
The forcer will be more complicated to make; it is essentially a transformer split in half with a permanent magnet between the two and ball bearings that ride along the platen. The force of the permanent magnet means you can use the linear stepper in either a horizontal or vertical position. The ball bearings maintain a 25 micron air gap between platen and forcer.
Someone in another thread mentioned the moving wires in the forcer and that it would be better if the electromagnets were in the platen. While this is possible, it isn't feasible or cost effective to build in a multitude of electromagnets within the length of the platen as more machining would be involved.
Everything you could ever want to know about linear stepper motor theory and design is in this publication: [issuu.com]
