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Machinist Mondays with Defiance
- Thread starter DefianceMachine
- Start date
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In this #MachinistMonday we are going to talk about... Sales. Wait!! What???
More directly, we're also going to talk about CNC programming and how we have connected the two, as it was asked here earlier.
CNC (Computer Numerical Control) programs are written with code that allows a computer to control movements and functions of a machine tool.
A CNC programmer can take a 3D model from a CAD (computer-aided design) program and use CAM (computer-aided manufacturing) software to post code that will control a particular machine to make the part.
Generally, a new program is written for manufacturing each part. If there were variations of that part, there would need to be additional programs written.
If you're the type of company that likes to offer a ton of options and variations, writing a new program for each variation would be a real issue. Enter: Subroutines and Macro programming.
A subroutine is a CNC program, that can be called up from another program. Let's say you're going to machine a complex pocket into several different parts. You write the subroutine once and write one line of code to call it up in each of the programs that require that pocket.
Macro programming is used when you want to incorporate variables, such as different lengths or right and left hand, for example. You can have a single "master" program that is driven by variables that makes 1,000's of different variations of the part. Macro programming also utilizes Logical Functions such as "IF" and "WHILE" to perform functions (machine features) when certain conditions (variables) are true ("EQUAL TO", "LESS THAN", etc.).
We are one of those companies that offers a ton of options, but we also make a high volume of parts. Our proprietary software allows the Sales Dept. to create a file for every action that we sell that sets the variables in the CNC control.
We use macro programming to make countless variations efficiently, giving the customer exactly what they need while keeping the cost down.
Stress Kills.
Machinists need to learn how to handle stress, and I'm not talking about the kind you feel when you scrap a part.
Metal has stress and it needs to be considered when you're trying to machine something to exact specifications including straightness, roundness, and perpendicularity.
It's like there are springs between the atoms that are pushing or pulling against each other. When material is removed, that allows the metal to move under that strain. A long piece of metal that has not been "stress-relieved" can bow like a banana if you remove a significant amount of material from one side. It's hard to make precision parts this way.
We do several things to manage stress:
- We machine all critical components such as bolts, receivers, firing pins, cocking pieces, etc. out of pre-hardened aircraft certified steels. These metals have been heat-treated to harden, temper and stress-relieve. If we machined material in the annealed (soft) state then hardened it, it would change shape and dimension.
- We handle the material gently, from off-loading the 12' bars from the truck to shipping the final product.
- We choose machining methods that do not induce additional stress into the steel such as Wire EDM, rather than broaching.
- We leave mass where we can. Our target actions have custom magazine cuts, heavy rear tangs, and integral scope rails that leave material on the receiver making bowing less likely.
- We are strategic about how we remove material. Techniques such as spiral milling are utilized to avoid removing material from one side before the other.
Bob Wright
Well-Known Member
I really enjoy this thread. I've been in the aero world as a machinist and a mfg. engineer for about 40 years. I love the way you have developed the manufacturing process straight thru to sales. Impressive. We had some amazing CNC capability for that business as well.
Great job!
Great job!
Fiftydriver
Official LRH Sponsor
You guys have had my business since Glen started Defiance. Heck, worked with him at Nesika and was glad he started his own shop and was willing to work with me designing and building my Raptor and now Stalker receivers. Could not be happier with your products!!
Before...
After...
There are several steps to turning a piece of bar stock into a finished receiver.
It takes a saw, lathes, 4 and 5 axis milling, a hone, wire EDM, and sinker EDM.
This 2 1/8" diameter bar of pre-hardened 416R is used to make stainless receivers with integral recoil lugs and weighs 9.44 pounds. The anTi X receiver has had over 90% of the mass removed and now weighs only 0.9 pounds. And it still includes integral 20 MOA scope mounts and integral recoil lug.
Modern machining and innovative processes allow us to make better, more accurate rifle actions.
Precision is everything.
The receiver is the heart of the rifle, and the hole going through the center, the feature that all others are based upon. The bore of the receiver is critical, as the diameter and straightness affect accuracy. Just as important is that the barrel threads in the receiver are concentric, and the receiver face and locking lug abutments are perpendicular to the bore. For this reason, we machine all these features in one operation.
When done properly, a barrel that gets screwed into the receiver will align perfectly with the two bores, concentric to each other, and under no stress from a receiver face that is out of square. This is the start of a superbly accurate rifle.
Drilling a precise hole through nearly 10" of hardened steel is not a simple task. We start by purchasing high precision lathes and having them equipped with high pressure oil coolant pumps. A common twist drill does not generally drill a hole that is straight, round, or a precise diameter. Gun drills do. After we drill and bore a pilot, the gun drill creates a precise hole straight through the receiver blank. We could leave well enough alone, but because the tool will wear, part number one and part twenty would be different.
Therefore, we gun drill slightly undersized and hone the receiver blanks to the finish diameter. The honing machine spins a mandrel with abrasive stones in the bore while moving it forward and back. The result is a smooth, round hole with a consistent diameter that is measured to .0001" resolution. That's 1/30th the thickness of a human hair for the non-machinist types out there.
We appreciate the updates. Unbelievable to think about how far machining equipment and processes have come in the past couple of decades. It would be awesome to cover some of the QA and stress testing in the future on this thread.
adk hunter
Well-Known Member
I'm fascinated with the process let alone the incredible tolerances!
I grind knives for a hobby and dealing with heat treated hardened steel is next level stuff!
I grind knives for a hobby and dealing with heat treated hardened steel is next level stuff!
Legacy Bolt Process
The bolts found on our Deviant and Rebel actions are manufactured differently than the bolts in the rest of our product line as they are machined with a full-length handle.
Manufacturing a one-piece bolt of this style is a bit of an adventure.
We start with a rectangular block of hardened steel from which we will get two bolts.
There is a deep hole through the center for the firing pin that needs to be concentric to the outside diameter. Drilling deep holes straight is always a little challenging, not to mention in pre-hardened 4340.
The handle is also a lathe-turned feature, but it is not perpendicular or centered to the body.
There are always multiple ways a part can be made, and at the end of the day we come up with a process that efficiently creates the best product possible. This part has a significant number of operations including a 3-axis mill, waterjet, 5-axis mill, mill-turn center, another 5-axis mill, and a 4-axis mill.
There are certainly faster methods to make a bolt for a rifle but when the product demands precision, elegance, and bomb-proof reliability, your options are much fewer.
Defiance anTi X Bolt unloaded with Robotic (Pneumatic) Grabber
This pneumatic gripper is now being utilized to run parts in a fully automated process.
These bolts are machined from a 6' bar, about 6" at a time.
The CNC program begins with a minimal amount of bar stock protruding from the main spindle.
After the front end of the bolt is machined, the sub spindle advances and grabs the bolt.
Next, the main spindle unclamps, allowing the sub spindle to pull the bar out farther before clamping again and machining the body of the bolt.
We electronically probe the bolt after each "pull," to ensure that we know exactly where it is "in space," and so we can hold tight tolerances across key features.
Lastly, the sub spindle chokes up on the bolt leaving only a small amount protruding and the back end of the bolt is machined to completion. We have now machined a complete bolt in just one operation, allowing us to create very precise and consistent parts.
Before the addition of the pneumatic grabber, the machine might sit for a short time while the operator finishes up some other task (like loading or unloading another machine). This may just be a minute or it may be 10 minutes. Minutes add up and we need to be as efficient as possible. With the addition of these pneumatic grabbers, the machine pulls the finished part out of the spindle, drops it onto a conveyor, and starts machining the next part.
Machinists and operators are still running the machines, checking and measuring parts, loading new bars of steel, making adjustments, changing and qualifying the tools, etc. There will be less "lost time" however. And when the crew is heading home for the night, a new bar can be loaded, and parts can be run for hours after we have shut-off the lights and gone home to bed.
At Defiance, we are constantly seeking ways to be more efficient, so we can better serve our customers.
It's a work of art, in the end.
sable tireur
Well-Known Member
- Joined
- Oct 8, 2010
- Messages
- 3,949
As with the entire thread, fascinating!
Thank you once again for taking the time and making the effort to keep us informed and up-to-date!
Thank you once again for taking the time and making the effort to keep us informed and up-to-date!
