To The Point - CNC Machining

May 17, 2012
by Mike Levy  
We talk to Straitline's Dennis Paulson, who, besides being a part-owner, has over twenty three years of experience on the machine shop floor. Much of that time has been spent running CNC machines, as well as on product development. Besides manufacturing their own pedals, stems, chain guides, and other components, Straitline also uses their CNC machining skills to fabricate products for both the aerospace and surveillance industries. It's fair to say that they know a thing or two about CNC machines.


    First off, what is a CNC machine and how do they work?

CNC is short for Computer Numerical Control. CNC machines are used primarily in metal component
manufacturing, however they are also used in many other industries such as textiles, and food and
beverage manufacturing. In a nutshell, a computer controls a very sophisticated electric motor, called a
servo motor, that then turns a ball screw (similar to a conventional screw, but the threads are half
round instead of 'V' shaped, and are filled with ball bearings that allow for lower friction and to eliminate
backlash
) that is attached to the machine frame. This screw drives the controlled axis back and
forth as needed. The computer can also control a rotary axis that allows the part or cutting tool to rotate.
Almost any shape can be created when two or more axis are combined.

Straitline CNC machine
The machine on the left is a nine axis MTM (Multi-Tasking Machine) that employs an upper five axis head intended for complex drilling and milling jobs. The lower turret can both turn and mill, but it is mainly used for boring and drilling operations. The machine on the right is a six axis Turn Mill Machine. It is similar to the MTM, but does not have the five axis milling head. It can still perform both turning and milling operations, but is more limited in the complexity of the milling.


    What are the advantages to CNC machining over casting or forging?

The two main advantages of CNC machining over castings and forgings are flexibility and precision.
While forging and castings don’t typically replace CNC machined parts, they do reduce the time needed
in a CNC or conventional machine. Surface finishes on a CNC machined part will typically be near perfect
and appear very consistent and precise, whereas cast or forged parts will be a little rougher, usually
requiring polishing or tumbling in an abrasive media to achieve a better surface finish


    Are there different types of CNC machines?

There are many different types of CNC machines in the manufacturing world and we are fortunate
enough to have and use virtually all of them, but I'll leave out the more specialized machines and focus on
universal equipment. Typically the most basic CNC’s are two axis lathes, then we move up to three axis
Vertical Machining Centers (VMC`s for short). We can add a fourth, rotating axis to a VMC to make
it a four axis VMC. Next step up from the four axis VMC would be the four axis HMC (Horizontal machining
center
). These machines typically have two or more work piece pallets that can be changed automatically
for increased production. As we carry on up the food chain we start to get into five axis, Turn Mill and Multi
Tasking Machines. Five axis machines can be either VMC's or HMC's, and have one other additional rotary axis
on either the cutting tool head or work piece pallet, allowing more sides of the work piece to be completed in
a single operation to allow very complex work pieces to be manufactured. Turn Mill machines are lathes
that also combine some milling to produce parts that are primarily round, with some milled features. These
machines are typically five or six axis machines. MTM's are the latest and greatest pieces of equipment in
the manufacturing world. They typically have seven to nine axes, and can be used to machine almost anything.
They combine the advantages of a full five axis machine with full turning capabilities as well. Most parts
machined on this type of machine will have a lot of milling and turning, and all will be completed in one process
cycle. As far as cost goes on CNC machines, industrial quality two axis lathes go from $40,000 - $100,000,
and the sky is the limit from there. CNC machines now reach into the millions! Almost all machines used in
advanced manufacturing also have the means to automatically change tools and remove metal chips or
shavings from the work area.

Straitline machine shop
Straitline's Defacto pedals are machined in a four axis HMC with a rotating axis that runs vertically. This allows the pallet to rotate so that machining can be performed on multiple parts and multiple faces of each part. This photo was taken as the machine was performing a tool check to verify that the cutting tool was not broken before performing the next machining operation.


    What sort of parts can be made by a CNC machine?

Almost anything can be made on a CNC machine, such as stems, pedals, sprockets, brake levers etc.
We use CNC for almost every part in our product range, with the exception of screws. Screws can be produced
on CNC's, but cold heading (which is similar to forging) is much more cost effective. Even the plastic parts
we produce are made in a CNC injection molding machine, and the mold used to produce
them are cut in house on our CNC metal cutting machines.

Straitline machine shop
An AMP pedal body nears completion in a four axis VMC. The machine component holding the pedal body is free to rotate around the axis for the length of the table to allow Straitline to machine all sides of the pedal in single operation. On the left you can see the cutting tool at the top, and at the bottom you can see a laser tool setter that is used to set tool lengths and check for broken tools in the process.


    CNC machines are certainly impressive, but they must have some limitations?

There are certain limitations to CNC, for instance you cannot easily machine sharp internal corners,
as rotating tools will always leave a radius in the corner being cut. Also, production of irregular shapes that
do not require extreme precision can be made much quicker with forgings and castings. These parts are
usually CNC'd after forging or casting to produce any size critical features. Almost any material can be
machined in some way or orther, and we typically machine aluminum, steel, titanium, and plastic, each of
which have hundreds or thousands of different alloys or polymers.



Stay tuned for upcoming To The Point articles where we'll explain the ins and outs of your bike.

www.straitlinecomponents.com


60 Comments

  • + 43
 As a machinist by trade and working on cnc's myself, i approve this write up Smile
  • + 4
 Lucky! I can write some code. Would love a job as an operator. These machines really bring materials to life.
  • + 12
 Not sure you would mate, setter / operator can be pretty boring stuff, especially large volume production items
  • + 3
 While i expect it to be boring at times as with any job, is it really that bland?

Dream job would be working in a factory like above making specifically bike parts.
Maybe it should stay just that - a dream.
  • + 3
 I'd love to be able to do this stuff!
  • + 6
 If you are looking for a job in CNC, come to Calgary Alberta Canada (Alberta in general really). There is large demand for labor in this field of work. You might not be making bike parts, but more than likely you will be hired somewhere.
If you are already in Calgary looking for work, send me a PM cause we are hiring!
  • + 1
 If only i was only 10 years younger I'd snap that job up muchomas
  • + 5
 I'm a Toolmaker by trade and have spent many hours standing in front of those bloody machines, programming and setting, hands and clothes stinking of coolant and oil..
Now as a supervisor of a CNC M/C shop in Canada I have to say it really has allowed me to work in other parts of the world and if you're good CNC machinist you should be able to get a job anywhere. I currently live in Vancouver and we need CNC machinist here too. We work on boring aircraft parts for the F-35 strike fighter - bikes parts would be more interesting.
  • + 1
 @muchomas, i'm a mechanical engineer and my work is mainly to project, model and then do the cam programs for cnc production. So in fact i follow the birth of a product from the scratch to the finished piece. I work mainly on medical tools and aerospace/energy turbofans. Some time ago i was looking for a job in Canada, cause i've always love that place...can you tell me something more about the job opportunities there? Eventually in pvt...Thanks!
  • + 1
 The Alberta oil and gas industry provides many jobs, and CNC related positions are just one of them. But there are hundreds of companies here seeking employees at the moment. The more skilled you are obviously the more valued you'd be, however many companies are willing to train for certain positions as well.

There are other companies not related to oil and gas as well (like mine) with a need for CNC personnel. So it depends on what you are looking for. Some places will have repetitive, less exciting parts to produce, but these same places might offer better long term stability. It's really all up to persoanl preference and what one is looking for in a career.

I'd say if you came to Calgary looking for CNC related work, there would be no reason you wouldn't have a job in a couple of days, likely the same day.
  • + 1
 Nice. I need more exxperience!
  • + 1
 Hey muchomas need any qualified welders? Hahaa Big Grin
  • + 1
 Oh look welding too dammit.
  • + 1
 Was out in BC skiing for 6 weeks this season and it just solidified my desire to move out to Canada. Been thinking about either Vancouver or Kelowna, although not limited to those. Being able to chuck the bike in the truck and head up to Whistler, Kamloops, etc for the weekend would be so perfect for me!

I've been a CNC machinist for the last 2 years at an aerospace firm, using both EDM and grinding processes and would be quite happy to carry on that path if it meant I could live in BC. However, I qualified as a proof inspector (both first principles measurement and CMM programming) and want to get back into that line of work. What kind of opportunities are there for this in BC? My main problem is I have no idea where to look!
  • + 1
 Muchomas thanks for the reply! Is there any hiring website where i can search for a job in Alberta or in Canada in general, just to know a little bit more and have an idea about companies, fees etc?
  • + 1
 @danbryody yep that would be also my goal...dream life. Not long ago i was searching for a cnc related job in BC on some online job sites like monster etc but couldn't find anything there...I was looking about send some curriculum directly to the factories like chromag, straitline etc...
  • + 1
 Me too however I'm lucky these days I seem to get a lot of 1 offs that nobody wants to do. Or lack the experience. Love to have a couple in the garage tho. I'd never ave to buy a bike component ever again.
  • + 1
 Best website I used to find a job in Canada - Vancouver is Craigslist.

vancouver.craigslist.ca

I only ever used this.
I found that you have to be in Canada before an employer will show interest in you.
  • + 11
 Yea but they should also say that forging gives preferential grain orientation giving you a stronger part, then only cnc critical faces. The result is a cheaper stronger, but less bling looking part.
  • + 3
 Yeah was gonna say the same thing, that's also a good reason to forge or roll the threads of a screw/bolt. Much stronger thread then if CNCed.
  • + 3
 or... you could forge the original block you are cnc-ing with a particular grain...
  • + 11
 One day. I will understand what these guys are talking about.
  • + 3
 I though it was misleading for the article to highlight the advantages of CNC machining over forging, while not mentioning the advantages of forging over CNC machining; forging creates a stronger part than machining, assuming it is done correctly.

Back in the day there were some crank manufacturers such as Kooka, that CNC machined their cranks without cold forging them first. I'd be surprised if you find any on EBay cause I'm pretty sure they all broke.
  • + 4
 @NorthEasternDH no you cannot do that , because the best grain is produced near the forging surface (not mentioning about the orientation of the grain and other aspects) , if you cnc forged block you loose the benefits.
Small companies have no choice, cnc is their only option, and they have to present it as an advantage, like in this article.
I prefer forged parts, they feel much more solid.
  • + 1
 Correct. Forging is overkill on bikes but I agree - beautiful processskill. Proper engineering an economics: Cnc moulds, cast, then cnc critical tolerances and some bling into the part - if you have to. Mould, tumble, little bit of cnc: Avid E1. cnc: Hope brake. E1 work because cast is the proper material and process for calipers.
Cnc parts are expensive not because of better materials. To keep expensive toolwear minimal machinist always opt for lowest quality possible aluminium. Cast does not carry weight penalty - if done right.
  • + 12
 This is my shit! Great write up
  • + 7
 Iv been in the machining trade for about 12 years now and worked at various companies and belive me it not all fun. After you set any machine its pretty much a waiting game (depending on batch quantitys). Most working enviroments are poor and the job at times can be tedious and mundane to say the least. Im lucky enough now to work at a great company but from what iv experienced over the years CNC manufactuting is a very dull trade. And i wouldnt reccomend it as a carear choice.
  • + 3
 Which is why you get into Tool, Die, or Gauge making! Then it's litteraly something different each time. Lots of theoretical calculations, metalurgy, design work, etc. And, still enough manual machine work to keep things interesting Wink - certified T&D guy.
  • + 1
 You know what mawsatron, you damn right in saying that is boring job, like at the moment I'm making 530 pieces with 2:30 minutes per job, not only is boring after the 100th pieces but its also tiring in the shoulders as well.
My working environment is pretty laid back since I'm partners with my old man in the business.

It's weird though, its like I can't stand the job and everything about cause I've been doing it for 18years and yet I see other peoples workshops and seeing what machines they've got, it gets me all floor inside.Smile
  • + 2
 atrokz - Not many people are wanting to be a toolmaker these days you think? Im the youngest toolmaker I know or have met but I looked at your age and saw that you were 30, as am I.

I just find it interesting when I meet younger toolmakers because they all seem to be old men who have gone nuts in the head working to close tolerances with manual machines.
When I started tool and die making in Oz, my class had about 25 guys, I finished my trade school cert with only 5 others, the rest dropped out. A few years later and they stopped teaching toolmaking at that campus.
Its hard to get a good toolie these days.
  • + 2
 Yeah husky360, it was the same with me when i was serving my time. Out of 30 apprentices i think there must now only be 4-5 still in the trade. And your right in 10-15 years time there will be very few time-served tool makers around. But saying that there always bringing out more advanced machines with a simpler interface which could take the place of the manual sections in most factories. Either way i must say the company i now work for is by far the best iv been to. But iv worked at another 5 engineering companys which were complete rubbish and i left the trade to work in a bike shop for a bit and intended not to go back. But the pay scale of a bike mechanic was a bit less than a machinist to say the least. I must just be happy in my missery. haha
  • + 2
 Husky: Yup. Which makes people like us rarer and in more demand. The world will always need tool makers, and will have to pay for the good ones. I take a lot of pride in what I can make. It might make me a bit of an elitist, but that's what tool makers are.... Elite. Wink My college class started with 60, and only 5 people finished their die.

So in summary, if you're bored with being an operator. Take a step up. Become a certified machinist so you can program yourself. And if you're bored with programing or being a general machinist, take the schooling to become a tool, mold, or gauge maker. You become an engineer/metalurgist/chemist/machinist/designer all rolled into one. That's where the real chalenges are.
  • + 1
 I machined/programmed for three years on CNC machines, and then moved to a CMM. I really like the challenge it brings (especially all the GD&T that is involved) and it really does keep the mind sharp. I have to say I really never got bored of machining as I love seeing a design come to life. Especially one that you've made. But inspecting parts on a CMM means you have to tell people they made a bad part, so you are the a$$. Really enjoyed the article though it did a good job of explaining for people who may not not the processes that go into their parts.
I also had the opportunity to do CNC/design work with Twenty6...loved being in the bike industry.
  • + 2
 Sorry to come and steal your youngest title but 22 Smile to be honest with you though im doin an apprentiship and im going to go into design because A. more money so more bike parts B. more jobs available in more companies, tool making is a dying trade in england and C. its dangerous! i dont wanna spend time off my bike because i caught my hand in a grinding wheel or a lathe. earn the money designing things, go home and ride. i know its a negative attitude, but dont get me wrong i love making things. seeing and using the parts you make is amazing. and very useful if the boss lets you make a few homers from time to time. great write up though love the machines
  • + 2
 I'm just stoked that there's a lot more machinists on pinkbike than I first thought..

We are a dying breed that's for sure. Not many people wanna do our job as a well here in western Australia, but our problem is that everyone wants to work in the mines ( we are experiencing a mining boom ), no experience required and base wage is 80k!
  • + 1
 philly on that note over on this side of the pond in the dakotas the oil industry is having that same boom...any old joe starts off at 100k+ with two weeks on two weeks off...
  • + 1
 I was an intern at a place that cut and drilled parts for the F-35 Joint Strike Fighter a few years ago. CNC is great technology buy it can definitely get boring quickly. That said, it is incredible what kind of things you can make with a basic 3 axis mill and small lathe. By the way, there are some companies making bench-top sized mini CNC mills for hobbyists that run a little of $1K USD + the cost of a computer, proper software, vice/tooling/etc. That's not a bad deal considering a hobbyist would never need the extra size/functions that come with the standard $20K+ machines, but it still is a pretty expensive endeavor.

I am planning on getting a manual mill in the next year or so - but plan on getting a manual one that I can easily retrofit to CNC (and still keep the ability to use it manually for quick/less complex stuff).

EDIT: Thanks to Straitline for the information. It is great to see people interesting in manufacturing. They seem to be a cool company who produces their parts in North America - which is why my bike is currently decked out in Straitline bling. Thanks for the awesome parts guys!
  • + 2
 Very cool, love machine technology of any kind, I recently had the pleasure of learning about injection molding which starts with a big block of metal that is machined. Amazing stuff. Endless possibilities.
  • + 2
 I am also a CNC machinist mostly making military airplane parts and its still amazes me that a 500 lbs forging of titanium in a weeks time can be picked up by hand. weighing in at 50 or 60lbs
  • + 1
 I too am in the CNC manufacturing arena in Calgary,Alberta, Canada.
Wonderous what these machines can produce with some good tooling and insightful programming.
Oil and gas parts pay the bills here though....no time for custom bike parts Frown
  • + 1
 To everyone who posted on here about moving out to Canada it ain't as easy as it sounds. If you do not hold Canadian citizenship. You have an upward struggle. I am not saying tat there are no jobs out the as there undoutably is bit the Canadian government and provincial government have a real protectionist view. I waited 9 months for a work permit to come work in Calgary and in the end I gave up as a better job came up in the UK. If you want to have a go that's cool but just be prepared to wait a very long time.
  • + 1
 There is going to be a need of CNC machinist's. Over the next 7.5 years, it's projected there will be a need for 2million CNC jobs. If your smart, like working with your hands, and want to be able to make this stuff, get to a school that teaches CNC.
  • + 4
 and without these lovely machines half of the mountain bike products wouldnt exist, thank you Jeebus!! Big Grin
  • + 3
 If you unclude the parts to make the tooling for the rest that aren't directly CNC machined, then there are no bike parts tht would meet todays standards or quality.
  • + 1
 Yay, Im a cnc machinist, I feel special now :-) Also got a 13x40 lathe and vertical knee mill in the garage. Machining lets me afford my bicycles +1
  • + 3
 I love reading this kind of stuff.
  • + 1
 Can't wait for my last year of college, I get to design something and bring it to life on a CNC machine. I'm thinking bike parts
  • + 1
 me too....but i need to fly to canada for do this! in italy there is no way to fin this kind of job for bike industries!
  • + 2
 Love to see Pink Bike started to talk things more than bikes it selves but further relative knowledge. Way to go!
  • + 2
 being toolmaker is where it's at...never boring...constantly keeping the brain busy...
  • + 3
 title made me think I was about to look at point1 racing machining...
  • + 8
 haha yea.. should have put "Strait to the point"
  • + 1
 i wish i had a cnc machine in my garage. the complex things you can program these to do! i would make my own pedals and stems.
  • + 1
 if i ever get rich i am going to get me a CNC machine as my first investment!
  • + 0
 We've done some machining/prototyping/r&d for a few big name mtb companies. I always love seeing mtb stuff go through the shop. www.peridotcorp.com
  • + 1
 Plenty of work for (fanuc control) CNC operators in Aberdeen, Scotland. It's all oil field work though, no bikes.
  • + 2
 Bring in some videos! I love me some CNC videos.
  • + 1
 Ah love seeing this shop.
  • + 1
 I dont see any Renishaw probing systems in them CNC machines .
  • + 1
 Man if i had one of these.... Id make a shitload of bikes

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