Resolved Question for the pros: Is V-Nail jamming on hardwoods a "pressure" issue or a "timing" issue?

[chuan shao]

Hi everyone,

I've been lurking here for a bit and have learned a lot from the old threads regarding machine maintenance.

I'm Chuan, a Technical Product Manager at XKY in Yiwu. We are currently tweaking the firmware for our new SmartFrame underpinners, and I'm hoping to get some "real world" feedback from those of you who use Cassese or Fletcher machines daily.

We noticed that when joining very hard woods (like Oak or Ash), older pneumatic machines often jam or misfire because the top clamp comes down too fast (or too slow) relative to the hammer driver.

My question to the pros here:
When you experience jamming on hardwoods, do you find it helps more to:
1. Manually increase the clamping PSI?
2. Or do you wish the machine could "sense" the wood density and adjust the clamping speed automatically?

We are trying to decide if we should code a "Smart Hardwood Mode" into our CNC controller, or if that is just over-engineering something simple.

We want to build tools that solve headaches, not create new ones, so your honest feedback would be invaluable to our engineering team.

Thanks in advance!
Chuan

 

[JFeig]

Is your question aimed at shops that cut moulding of various densities when cutting mouldings for custom jobs for for production machines that will cut 1,000s of meters of moulding in a factory situation?
I understand that it can be done; but, should it be added to a machine? CNC machinery has made great changes to manufacturing as has CADCAD design.

I can see several negatives to having such a pressure sensor being added:
if you are cutting a dense material and switch to a drastically less dense material - how will this work without user error?
reliability - can the sensor be turned on/off by the user(a bypass mode) to continue using the machine.
serviceability - DIY or calling a service tech? - downtime to repair - hours - days - weeks
cost to replace - the sensor - program update - PC board
initial cost

The standard process is to just increase the pneumatic pressure. As you know, the air pressure varies from your air source per the specification limits of its regulator switch mechanism. When changing moulding profiles, the operator readjusts the height of the clamp as a normal procedure.

 

[alacrity8]

I believe that Jerome has a lot more experience in the industrial side than most of us.
As such he asked questions that are all excellent (and I never would have thought of).

My only thought/concern is that you are asking about the speed of the clamping.
In my experience you want the clamp fully engaged before the hammer/driver is activated, so the speed shouldn't matter, only the pressure.

Other than that I have no experience with "Smart" tools in framing. We have a newer CMC, but all of our other equipment is at least 3 decades old, or new but made from the same old plans.

 

[wpfay]

The other high production v-nail machines use barcodes for each profile which determine the positioning of the v-nails, the lengths to be used, the kind (hardwood or softwood), and the pneumatic pressure needed.
The vertical clamp pressure is greater than the driver pressure and holds the frame in position continuously throughout the joining process. The horizontal clamp holds the frame securely to the fence in the same manner, only releasing after the v-nails have been driven.

 

[chuan shao]

Wow, thank you all for the incredibly detailed responses. This is exactly the kind of "battle-tested" insight we can't get just by running simulations in the factory.

To answer @JFeig 's concern about reliability: You hit the nail on the head. We are terrified of adding complex sensors that might fail in 3 years and leave the user stuck.
Based on your feedback, I will recommend to our team that we MUST have a "Manual Bypass Switch." So if the smart features ever glitch, the user can flip a switch and use it just like a classic pneumatic machine. No downtime.

@alacrity8 , you are right that pressure is key. The reason we are looking at "timing" (or speed) is that with some very dense hardwoods (like Hickory), if the clamp slams down too fast, it can sometimes shock the frame or not allow the wood fibers to compress fully before the nail fires. We want to delay the firing by milliseconds to ensure the wood is "settled."

@wpfay , that is an excellent point about the barcode systems. We have the flexibility to adapt the design based on real demand.
Perhaps the best approach is to offer this as a "scalable" feature? For a shop processing less wood, the standard mode works fine. But for high-volume production, we could integrate a barcode reader to auto-set the parameters. This would add significant value for growing businesses without forcing the smaller shops to pay for features they don't need yet. We will definitely look into this "modular" approach.

This gives me a lot to think about. We might scrap the "always-on sensor" idea and instead focus on a robust "preset/modular" system where the smart functions are there when you need them, but don't get in the way when you don't.

Really appreciate the welcome and the honest advice!

Chuan