Vises vs Fixture Plates


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Thread: Vises vs Fixture Plates

  1. #1

    Default Vises vs Fixture Plates

    I've started using fixture plates more and more. If I want to make more than one of something fixture plate more easily allows me to use the full work envelope of the machine. In fact, in excess of the work envelope of the machine in some cases. Everybody's application will be different, but I use a lot of standard width aluminum flat bar. You might think that would be perfect in a vise. In fact for years I thought so too. In order to cut two pieces I would mount two vises, and use G54,G55 work offsets. It works very well, and halves the number of tool changes to do a job. I've got a stock desing 2x3 inch mold I make fairly often. I could put two presized pieces of stock in the vises, get my offsets, and cut a complete mold in one shot. Maybe I could cut 2 molds if I felt comfortable putting two pieces in each 6inch vise, but I just don't trust a vise to clamp both pieces well enough for all operations. As you may be aware flat bar varies in width and thickness. Usually from over size to just barely over size. I supposed if I did MORE prep work that would be less of an issue, but then its more prep work. More time I am not at the computer catching up design work.

    My solution was going to a fixture plate. So far for the Tormach I have made 2 of them, and plan to make 3 more. It was a lot of work to get everything dialed in and measured, but now I have a 2D cad model of "my" Tormach mill table. I set two alignment pins in the bottom of the plate, flipped it over and to machined place. I pull the pins against the center slot of the table and clamped it in place. Next I pocketed out countered bored bolt holes for the plate to set button head bolts to lock it in place. It gets bolted down, and a register mark in machined the exact center of the machine travel. Finally machine a partial flat on each end for using a stop to take one plate off and put another one on. At this point its a fixture blank.

    My first simple fixture plate is with slots (and clearance \underneath) for 2 inch wide flat bar. I can machine every part of 4 of those 2x3 mold plates in one setup. I just drop a long piece of flat bar in the slot, and its held by a bunch of edge clamps. Each clamp moves individually when its tightened so its firmly clamped at several points. All the features are machined and then its split with a semi slotting operation. I don't worry about cutting all the way through either. There will still be plenty of support for stock in the future. I made that fixture plate with 3 such slots. In one setup with 12 times fewer tool changes I can machine 12 parts to make 6 complete molds.

    I made a similar one for two pieces of 4" bar stock. I've used it several times to cut 4x6 mold plates 4 parts at a time. I mounted a gage pin to fit my register, but so far repeatability when I set the plates has been as good or better than the repeatability of the mill's homing process. I use the register atleast the first day when I set the plate anyway.

    Then I design jobs around the fixture plate when cutting multiple parts. No more need to keep track of multiple work offsets if I just start with a slightly over length piece of bar stock.

    I have wished I had a vise on the machine a couple times, but I do have 4 other machines in the shop that still have vises mounted on the table.. Five if you count the little toy mill drill. The Hurco still has 2 8 inch vises dialed in on the table. Its got both cut in place steel step jaws and soft step jaws labeled for each vise.

    Fixture plates are not as useful for single one off unique parts or repair jobs, but for small scale production they really helped me juice up my productivity. I'm seriously considering them for my two quick change fast spindle machines.

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    Bob La Londe
    http://www.YumaBassMan.com


  2. #2
    Member AUSTINMACHINING's Avatar
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    Default Re: Vises vs Fixture Plates

    [I use a hybrid approach as I don't use fixtures too often. I have two vises on the table trammed together. I design the fixtures to span the two vises. If I was doing production, and wanted to keep vises on the table, Orange vise makes a pallet system that works with their vises that looks pretty cool.

    Vises vs Fixture Plates-2020-01-18_19-52-11_resize_99-jpg



  3. #3

    Default Re: Vises vs Fixture Plates

    Nice setup.

    I did consider a pallet system. It would be nice to be able to preload stock.

    I went with the fixture plates for now because of the ability to design them to use more of the working envelope of the machine. The three little Speedmasters still have grinder vises on them with machined steps in the jaws for now. I am considering fixture plates for two of them though too. The third lighter Speedmaster mostly just gets used for engraving. The biggest headache of the fixture plates is I do have to change them out periodically, and I have to take the time to completely clean the table every time. No swapping them out in a hurry and just go.

    I considered fixture plates for the KMB1 as well, but its nice to have it setup more for job shop work with a pair of vises on the table (also with stepped jaws). I use it a lot for prep work and second op work for the other machines. Its kind of funny. I had originally planned the Tormach for prep and second op work.

    Bob La Londe
    http://www.YumaBassMan.com


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    Member Steve Seebold's Avatar
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    Default Re: Vises vs Fixture Plates

    I make a lot of small parts on my PCNC 1100 and when the job warrants it, I’ll make 2 fixtures then I can have one in the machine running and the other one out on the bench being reloaded.

    You can buy GOOD PARTS or you can buy CHEAP PARTS, but you can't buy GOOD CHEAP PARTS.


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    Member deadlykitten's Avatar
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    Default Re: Vises vs Fixture Plates

    hy bob ... please, will you share some photos ? kindly

    we are merely at the start of " Internet of Things / Industrial Revolution 4.0 " era : a mix of AI, plastics, human estrangement, powerful non-state actors ...


  6. #6
    Community Moderator Jim Dawson's Avatar
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    Default Re: Vises vs Fixture Plates

    We use a pallet system. We bolted a 1 inch MIC6 plate to the table and drilled it for various setups including vice bolt holes. Prior to bolting down the plate, we waxed (several coats) both the table and the plate so the table is protected. We installed drill bushings in various locations that are the aligning holes. All of our pallets are designed to drop pins into the drill bushings.

    The pallets are made on a special fixture that spaces the pallet off of the MIC6 plate so they can be drilled & tapped thru as needed.

    These parts are for our own in-house product, so holes for hold down are designed in where needed.

    Here is a pallet shown ready to accept the raw material. Material is clamped down for initial drilling using tapped bolt holes either in the fixture plate or the MIC6 plate.
    Vises vs Fixture Plates-img_2535-jpg

    Parts in process
    Vises vs Fixture Plates-img_2538-jpg

    And ready for a second opp which is fixtured in in soft jaws in the vice.
    This is a low volume part so we only run 3 pair at a time.
    Vises vs Fixture Plates-img_2541-jpg

    These parts have their own fixture plates, we run about 50 at a time. These start out as a 14 x 30 x 1/2 inch 6061 plate which is drilled to accept the 10-24 hold down screws. Once all the screws are in place, press Go and come back in about an hour.
    There is a second opp on these parts, they get drilled & C-bored or drilled & tapped. This is done in another fixture about 15 parts at a time.
    Vises vs Fixture Plates-img_2533-jpg

    There are some things that make sense to do in a vice, but for a lot of parts, pallets and/or fixturing are the way to go.

    Attached Thumbnails Attached Thumbnails Vises vs Fixture Plates-img_2533-jpg   Vises vs Fixture Plates-img_2541-jpg   Vises vs Fixture Plates-img_2535-jpg   Vises vs Fixture Plates-img_2538-jpg  

    Jim Dawson
    Sandy, Oregon, USA


  7. #7

    Default Re: Vises vs Fixture Plates

    Quote Originally Posted by deadlykitten View Post
    hy bob ... please, will you share some photos ? kindly
    Sure. Setting up a job right now to run off 6 molds (12 parts).

    Thanks Jim. A Base plate with secondary fixture plates is a great idea. I may look at that down the road. It would allow for preloading stock, making smaller fixture plates, and less **off machine finishing.

    ** I had to drill and tap for the edge clamps on my fixture for 4" bar stock manually off the machine.




    Bob La Londe
    http://www.YumaBassMan.com


  8. #8

    Default Re: Vises vs Fixture Plates

    Here:

    Attached Thumbnails Attached Thumbnails Vises vs Fixture Plates-kimg0849-jpg   Vises vs Fixture Plates-kimg0852-jpg   Vises vs Fixture Plates-kimg0856-jpg  
    Bob La Londe
    http://www.YumaBassMan.com


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