Is CNC an option?

[Brodie Brickey]

I've been looking at designing some custom pen kits. If I put the entire 3D design together and pass it to a manufacturer, I'm looking at 3,000 pcs minimum order. Not only is that a lot of pens, but if my design is off I'm out a lot of money. As a result I'm thinking about the possibility of CNC to mill the pen tips, center bands, and end caps. I figure I can order the mechanisms and inks from a pen manufacturer.

Can this be milled on a home / hobby CNC? Due to the size of the item, I think I'd need something with pretty accurate indexing, but a small size. Any recommendations on which CNC or whatever?

I'm sure there's a lot I don't know (especially with no CNC experience), what else am I forgetting?

These pictures aren't my designs, just something to help you visualize.

deco-centerband.jpg gent-rollerball_l.jpg

[Steve knight]

sure you could do it. but expect some money and a lot of time to learn to do it. You may need some classes ot learn to operate your tool and design items to cut on it. so How much can you spend to do it and how much time? those are the first questions you need to work out.

[Brodie Brickey]

My local community college has coding classes for CNC as well as a number of fabrication related education available. My day job is programming related so I'm not too worried about the coding aspects.

When I look at the CNC related projects out there, I mostly see mostly sign making or raised/recessed carving. I haven't seen what I would consider examples of 'automated lathe turning' related items.

As for cost, I'd like to get in for under $15k since this will be an extension of my side business.

[Steve knight]

There is no real programming anymore. it is more learning to draw and to learn the software to make the toolpaths that control the tool. learning what cutters work the rpms and how much you can cut at once and such. Learning to use the tool learning what it can and can't do.
well metal working is a whole different ballgame then woodworking and such you see here.

[Wes Grass]

If you want to run those rings in qty, you're looking at a turning center with live tooling. Might find one at auction for 20'ish if you look long enough. If it's got the right angle tooling you need on it, great. If not, you'll be scrounging for that or paying $5k or more for new. (A nice dual spindle Mazak with several live tools went for about 25k here a couple months ago. But it was 14 feet long and weighed 18k lbs, so not an easy thing to sneak into your garage)

Programming? 4 axis required, $4k for Visual Mill. I don't know what might be available on the 'hobby' end of the spectrum.

A 4th on a small mill will work as well, loaded up one at a time, but you still need the turned pieces.

Might post on Practical Machinist under 'Manufacturing Resources'. Should be a number of people there that can supply finished parts in smaller than 3k qty, or turned blanks if you want to do the milling yourself.

[Brodie Brickey]

Wes,

Thanks for the info. I'll give that a try.

Brodie

[Michael Simpson Virgina]

First off I have to say the purchasing a CNC machine for this is a very bad buisness desicion and one that is likley to fail if not though out properly. If you really think you have a viable product the best choice at this time would to be to get someone with a CNC to make a few of them for you. Say 50 or so.

If you can move 50 of them then you can think about going full bore. But to purchase or build a cnc and to learn all that is required on the chance that you have a product that will sell is not a good idea.

[Steve Godding]

I agree that there are a number of things to work through on this, and buying a CNC in the hope of learning it fast and jumping right into business is likely to fail. However, if you want to try CNC turning and perhaps start a bit smaller, look at something like a mini-Arty from Legacy. It's intended for this type of operation (although not with an automated tool changer), the guys at Legacy have experience writing and helping customers write the turning parts of the program, it's a lot less expensive than 25k and it's small. There are guys turning pens on Legacy Artisan and Arty-type equipment today. It will only do the work one-at-a-time, though.

[Bruce Boone]

I've made a lot of high end pens and will say that it's a tough market. People with the money to buy those want name brands. There's a market for medium end ones like the $200 to $500 range. My advice would be to start by making the first few on a hand lathe. See if they will sell as you think they might. Making a living with pens is a very hard thing to do. I know of only 2 or 3 people that make over $100K from pens. Doing less won't pay for the big time equipment. I have a buddy that sells kit pens, but he markets them well and does custom lasered designs for groups in the $300 range. He does very well with them and recently bought a big CNC lathe to help speed things up, but that is a major investment and one you should not take on unless you know you have a market. It is possible to make do with a small CNC lathe, but honestly, doing them by hand is about as good as using one of those.
A lot of the centerbands like the ones you show are lasered with a powerful laser. Not many people other than the big factories in China have equipment like that, so they charge their bucks and or demand large batches. I know I will when I get mine in.
A tabletop mill like a CNC Sherline mill from MicroKinetics or similar ones can do it, but they will break a lot of small cutters when doing deep engraved designs.

[Scott Shepherd]

If you want to do stuff with that level of detail around it, as mentioned a lathe with live tooling, but I'll take it one step further. You want a "Swiss type" CNC lathe. The work moves, not the tool, when cutting. Citizen, Star, Tsugami are a few of them.

Have a look, that's 3/4" diameter material being cut. They make a smaller machine :

[Andy Birko]

I know nothing about making pens but I thought I'd throw this out there - from the pics you've posted, lost wax looks like it would be a great way to cast the outside patterns of the rings. High quality 4 axis machines for wax are "affordable". Any old lathe could then machine out the ID to what you need for a high quality product. You should be able to way out perform the lasers and such with a technique like that. Check out the rings (i.e. jewelry) that are made with lost wax 4 axis CNC - amazing stuff.

[Bruce Boone]

Swiss Turning Centers are high dollar. They usually are in the $400K to $600K range. If there are used ones available, there's probably a good reason for that, as they should be pulling in $6000/month payments. I owned one for a few months. It couldn't make the parts I needed, so had to sell it back at a huge loss. I learned my lesson on that one. Definitely find someone with one and don't try to do that part yourself unless you have a contract for tens of thousands of pens.

Picture 008.jpgPicture 012.jpg
Casting isn't a bad option. These were printed in wax then a urethane mold was made from the master. The mold allowed the caster to inject wax then do lost wax castings. The molds work for dozens up to hundreds of parts before a new master has to be made. These ones are silver. There's a bit of learning curve and lots of expense with parts done this way, but they can print it from your 3D file. There's lots of handwork to get the parts round and to finished dimensions, but the parts could significantly increase the perceived worth of the pen. Don't fall into the trap of thinking the parts for a pen will be as cheap as ones from Woodcraft or similar places will cost. The Chinese make boatloads of the same design over and over. They can dial in costs that way. Onesies of a special design might cost 20 times or 50 times those amounts.

[Brad Knight]

Well, I'm in the process of buying a ~$15,000 CNC machine with the indexing lathe and all that... and that said, if I woke up and decided I wanted to make those parts, I wouldn't do it on a CNC unless it was 1-2 and they were each individually designed. I mean, I believe I could, but I don't think that's the correct process for the part.

I would look at spin casting. I've seen it done and it would much more cost effective, plus there isn't the CNC learning curve to deal with. Google tekcast spin casting for a youtube clip of the process. You can go from design to product testing, back to design, to production and then plating/finishing a lot quicker (I'd think).

[Scott Shepherd]

Bruce, great point, I wasn't clear in my post. You should be looking for someone WITH a swiss style lathe, not looking to BUY one. Parts coming off of a swiss are some of the most economical machined parts you'll find. They are incredibly fast and accurate. They are also made for large runs. A swiss style will eat up a 3000 piece job in no time. There are loads of people with them out there, that have their machines sit idle. It's a hard machine to keep busy because it's so productive. So you might just find someone that has one and can work with you fairly easily. Just start calling machine shops around town and ask them if they have a CNC swiss style lathe with live tooling.

Whether or not it's the best way to make what you want, I have no idea. I'd listen to Bruce on that one, he's living in the real world of that market, where I'm looking at it from the machine shop angle, and just saying "yes, this machine can do it" angle.

[Richard Rumancik]

Brodie - what metals are you planning to use? I did not see that mentioned. Casting may be a good alternative, but some of the processes suggested (investment casting, spin casting) are limited as to what metals you can use. Spin casting is usually low melting temperature metals like zinc and pewter. Investment casting, at least what is commonly used for jewelry, generally uses gold/silver for jewelry but you could also cast low-temp alloys using this as well. You might be also to do brass with investment casting but not spin casting (which uses silicone molds.) So the process is somewhat dictated by the material you need.

I think investment casting would work for the rings. It could be cast and then the ID and ends turned on a lathe. In the picture, it looks like perhaps the OD was also turned after applying the dark paint or coloring, but I'm not certain.