High-speed jointing head moulders
For custom runs, you would be better off with a non-jointed machine to start with. As you go with longer runs, go to a jointed machine.
Before you purchase a molder, take some classes and learn about the machines well. A molder is a complex machine--if you are making custom runs and the first piece through is not correct, you can blow $80 of wood in a hurry, trying to get a piece correct so that you can make your run. There is more to it than just running a cant through.
A run of 5000 linear feet is necessary before it is feasible to use a jointed machine, because it takes extra time to set one up. A jointed head molder is almost twice as expensive as a non-jointed machine and more complicated to set up. A jointed head molder requires you to be fluent in the grinding of your knives because you have to grind a jointing stone that is the exact profile of the knife you are using and matches up with that knife at a precise angle. When a jointed head machine joints your knife, it evens up the knife so that they are all the same. You are actually dulling the end of your knife to achieve this. You have to know how to grind.
With a non-jointed machine, no matter how good you are at grinding, one knife is always going to be higher than the others. Even if it is only in the thousands of an inch, only one knife (even though the other knives are cutting) is going to be cutting on the finish. The knife marks that you see on the finished product will be the result of the highest knife only. With a Wienig non-jointed machine spinning at 6000 RPM, you can figure about 32 fpm. Plenty fast enough for manufacturing custom molding.
From the original questioner:
We are not totally new to the moulding business. We have made radius mouldings since 1990. We purchased a small 4 head moulder about a year ago and our business has flourished. We have never taken classes, but we intend to, as we are laying more money on the table for better machinery and we will be making our own knives instead of outsourcing, as we have been. Most of what we do now is s4s, so it doesn't take rocket science to do. I do realize that we need training for running different profiles.
When deciding between non-jointed or single knife machines and jointed machines, you should consider the normal length of run and the cost of the machine. You need to also understand the additional cost in setting up the high speed moulder. The cost of the jointing stones and shaping them adds up.
If the normal length of run is over 5,000 lineal feet, a jointed moulder is worth looking into. It takes about twice as long to set up a jointed machine as it does a non-jointed one.
If your normal run is under 5,000 lineal feet, a non-jointed machine is the one for you. In either case, the tooling and grinding of that tooling is the most important part of the operation.
Without a doubt, attending a class is a good move. A wide number of machines can be seen and used at different schools. The more machines that you get a chance to work on, the better it will be for you when making your decision.
Dave Rankin, forum technical advisor
You can buy a jointed moulder and run it like you would smaller runs non-jointed. If you think your business may grow into needing a jointed machine, it would be better to get the jointed machine first. All moulders are expensive and the trade-ins are not that great.
For high quality custom work, which runs typically in volumes from 50 < 3000 lin.ft., you should focus on a non-jointed through-feed configuration machine with 4, 5 or 6 spindles, depending on the range of profiles, wood species and condition of wood to be run.
Take special care of setting procedures together with tooling and grinding choices, since many false claims are made by some who do not have the technology in their machines.
The only advantage I think you would gain in your situation is the ability to run the occasional extremely wide thick profiles. I have one Profimat 23, and after three years of use it has been a real performer. It does have limitations on the profiles it can handle. I also have a Unimat 17 with the same problems.
A good all-around machine would be one with outboard bearings, larger spindle diameter and enough rpm to get you 60 fpm and still keep a good quality finish.
I also have a Hydramat 23. It is a 60m machine with a max feed rate of 180 fpm.
I have run 1/4 x 3/4 scribe and 1 1/4 x 9" crown profiles. These were not all run at high speed, but the versatility is a major advantage. The concept of running a jointed machine is simple. The ability to run high-speed productively requires a top-notch operator and extremely accurate tooling. Conventional runs are a lot more forgiving.
I agree with all the other statements on run lengths. I have made the break at 10,000' before I will consider a high-speed run. The problem with a high-speed run is competition. Large runs are normally high competition and low profit margins. I like the concept of Wienig's Unimat 23. I believe it's the yellow line. It's not a jointed machine but it does have higher rpm spindle rates, which could give you a high quality finish at a good feed rate. Try to see the equipment in a productive operating environment.
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