Six Things You Need to Know About CNC Fixturing

Fixturing is arguably one of the most complex and challenging (yet fun) parts of machining. Having the proper workholding and fixturing can make or break a production run, but in some cases, it can even break your part.


Expanding the Saunders Machine Works Fixture Plate Line

At Saunders Machine Works, we understand the value of a small machine shop. Our machining story started with a CNC mill in a small New York City apartment. With that in mind, we have begun expanding our line of fixture plates with one goal in mind: to provide products that will guide a machinist from their first CNC mill through their first VMC. From the Tormach 440 in a basement shop to the production-capable 1100MX mill, we have been building out our fixture plate line to fit your budget and your needs.

Steel Fixture Plates

Our “flagship” model, these steel fixture plates are the strongest and most durable. They are machined from 4140 steel, precision ground, and hardened to 30 Rockwell C. All holes are bored to .5005 ± .0002” to fit a standard 1/2" dowel pin. Perfect for MX level machines and anyone running production on their Tormach, these plates are designed to stand up to constant use and should see little wear and tear. If you’re using your Tormach every day, this is the plate for you.

Anodized 7075 Aluminum Fixture Plates

Our most popular plate among Tormach users, this plate offers the best of both worlds. The 7075 aluminum with a black anodized surface has proven to be durable and scratch-resistant while remaining inexpensive and light. These plates provide a great value and help bridge the gap between hobby and prosumer machines.

6061 Aluminum Fixture Plates

These plates are designed with one purpose in mind: getting the hobby machinist straight to making parts without breaking the bank. These fixture plates are lightweight and inexpensive but are still bored to the same tight tolerances as the other SMW plates. Due to the bare aluminum composition, these plates are more prone to light scratching and cosmetic defects, and they may see more wear over their lifetime than our other plates. Priced competitively ($299 for a 770, $399 for an 1100), these plates are great for beginners and hobbyists.

Mod Vise System

All SMW fixture plates are compatible with the popular Mod Vise, one of the most cost-effective, flexible workholding solutions for CNC machining. The Gen2 Mod Vise is now compatible with soft jaws, smooth jaws, and Talon grips. The flexibility of the mod Vise system allows you to hold parts of any size, and the low-profile nature maximizes the Z work envelope.

Pierson Pallets

In addition to our fixture plate line, we offer pallet systems for even more diverse fixturing options. New to the SMW lineup is our Pierson PPS compatible pallet – a 6061 aluminum pallet with our standard ½”-13 hole pattern to allow for use with our existing Modular Vise System and general fixturing. Pierson Workholding Mini Pallets now ship as directly compatible with SMW fixture plates; this is an excellent combination for machining and production workflows on Tormach machines!


Fixture Plates and Why You Should Use Them

Machining parts is easy... work-holding is the hard part! Fixturing, part setups, and work holding is a never ending skill. Any time I have the chance to tour a factory, walk a trade show, or talk shop with another machinist, I try to learn as much as possible about workholding. There are countless creative uses for vises, soft jaws, 1-2-3 blocks, toe jacks, and other tools. A good workholding setup can mean improved surface finishes, more accurate parts, and better tool life. Furthermore, setups can simplify short production runs, ensuring that all parts in the batch meet tolerances. Process reliability is a key part of machining and making. The easier it is to implement good fixturing, the more likely you are to embrace it! One of the best ways to increase the functionality and work area of the machine table is with a fixture or tooling plate. Check Out the SMW Tool Plate There are three key benefits to a fixture plate:


Workholding of the Month: Tombstones

When you’re looking to do production work, or just looking to machine multiple parts at the same time, a CNC tombstone provides a way to fit several parts for many different operations into the same setup. When combined with an automatic tool changer (ATC), a tombstone can provide an easy solution to milling multiple parts that you can set and forget while your parts are machined. Tombstones, also sometimes known as pedestal fixturing, tooling tower, or fixture block, have two or more sides, typically four, that you can affix parts directly or attach various fixture plates. The Tormach Tombstone is designed to fit on our 6” or 8” rotary tables and the fixture surfaces are left as-cast, allowing users to fully customize their workholding by machining the tombstone to fit specific applications. There are two ways to really utilize tombstone manufacturing.


Workholding of the Month: Double-Sided Tape

Workholding is a vital piece to any machinist’s arsenal of knowledge. So much so that there is an endless list of books solely dedicated to workholding design – like the two we have available, Jig and Fixture Design Manual and Basic Fixture Design. Some corporations even hire engineers to do nothing but design more efficient ways of keeping work in place. Even though workholding is incredibly important, it is often one of the last discussed elements of machining. What adds more to the confusion is the fact that, generally, workholding can be done a dozen different ways for any given part. When working with machine tools, it’s easy to forget that some of the best tools are those that we used in elementary school. Double-sided tape can be finicky, but in the right situation, it can make life much easier when dealing with a thin or odd-shaped part. John Saunders at NYC CNC recently had to hold down an encoder wheel he was making for a chemistry lab. The steel work was 0.012” thick, which can create quite a challenge for holding. Saunders took to his office supplies, and used some 3M double-sided tape to keep the part in place. With the help of a pre-cut aluminum fixture and the tape, this steel part was created without a hitch. [youtube]_LheMe0zvAo[/youtube] We’ve even used double-sided tape in our showroom. During a local STEM day hosted at Tormach Headquarters, we were planning to engrave and hand out aluminum dog tags to kids attending. The tags ran about 0.045” which is far too thin to hold in a vise, at least efficiently, so we took to creating a large fixture plate and using tape. The fixture plate housed the dog tags nine across and seven deep, providing a much more efficient way to engrave the Tormach logo onto several pieces before the big show. What’s the strangest workholding you’ve seen? Email and let us know!


More Fixture Plate Ideas for Workholding Setups

Last week we talked about using fixture plates for quick and repeatable  setups, and asked blog readers to send us pictures of their fixture plate set ups as part of a contest.    The winner of last week's blog contest is Fred Francouer from Université de Sherbrooke in Quebec, Canada.  Fred's designed a clever setup that allows him to quickly attach several vises, a 4th Axis, work holding chuck, and even the Duality Lathe to his PCNC 1100.  Thanks for sharing, Fred - you're the winner of a custom Tormach Shop Shirt. What we really like about this fixture plate system is how the individual components are designed to stack and install on each other.  Check these out:

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