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View Full Version : Cutting wooden letters and shapes - purchase help for a newbie please!



kemo_2002
27-08-2012, 11:28 PM
Around 6 months ago, i started my own business selling my handmade items, i am fortunate that my other half works on a very large CNC (he makes firedoors) and has been making my letters at work for me.

Unfortuantely it is a bit too risky when he should really be working, and eventually we would like to get one for our outdoor workshop. I have however, no idea what to look for, and was hoping if i tell you what it would be used for, others could help suggest something suitable? and the type of programme needed

MDF wooden letters roughly 6" high 1cm deep.
MDF wooden shapes - eg hearts, stars, plaques ect

would also like to do thicker freestanding letters, cubes and other thicker shapes.
possibly engraving into stone, this is just an idea however i am not sure the same machine can be used?

I hope this is enough info, the only thing i havnt included is a budget, becauaw dont really know how much we are talking, obviously the cheaper the better, but does the job i need it too.

Thanks a million guys

JAZZCNC
28-08-2012, 12:16 AM
What size sheet material do you want to start with.? Larger the size the more the machine will cost.

Forget cutting stone with the same machine it's a completely different machine and cutting spindle which requires lots of water which doesn't go well with MDF.!!

The budget makes a massive difference and if your looking to buy a decent size machine say 1250 x 1250mm which is half sheet of MDF then expect 4-5K for a decent machine with software.

If you or the other half have the skills and tools to build then you can cut this down to 1500 -2K ish.?

It's not difficult if you have the time and desire along with some help from here with design and component advice then you'll make a very good machine easily capable of what you want for a fraction of the price.!

kemo_2002
28-08-2012, 01:07 PM
Hi..thankyou for your reply...Im not needing to make 100s of letters a day probably 10th0 a week perhaps..I ideally wanted to start both something small and upgrade at a later date..its only a small business run by myself alone. unfortunately I wouldntt have a clue where to start making one, did think about it, but spending all that money on building something have no clue about is too worrying.

irving2008
28-08-2012, 01:28 PM
...probably 10th0 a week perhaps.. Was that 10 a week or 100 a week?

If the letters are 6"/150mm high on 11mm MDF and you are talking abut low run rates then if you started with a small blank precut say 170mm x 170mm you'd get 98 letters out of a sheet of MDF with <5% wastage. You could get B&Q or whoever to precut these blanks for a small sum about 10. In that case you could get away with a much smaller/lighter/cheaper machine around 500 - 600 new or even less if you picked up an ebay used bargain. You could even build a suitable machine for that sort of work from MDF for 300 or so, to an existing established design, which for someone with your evident hand-working skillls should be relatively straightforward.

While obviously cutting from a full or half sheet of MDF is preferable from a speed/materials cost/job run perspective (especially if you were doing a 100 a day!) its something you could then aspire to as the business develops, by which time you'd have the knowledge/skill to make the more complex decisions about specifications and whether to buy/build.

Heres an example of what you could buy (not suggesting you get this one, before Jazz leaps in lol) http://www.ebay.co.uk/itm/Sable-2015-CNC-ROUTER-ENGRAVER-mill-PCBs-engraving-/251139212784?pt=LH_DefaultDomain_3&hash=item3a791045f0

kemo_2002
28-08-2012, 03:03 PM
100 week :-) hthankyou, I was just trying to get ideas really, the one thing I don't want to do is get a too basic one only to find I want expand quicker..

irving2008
28-08-2012, 04:10 PM
100 week :-) hthankyou, I was just trying to get ideas really, the one thing I don't want to do is get a too basic one only to find I want expand quicker..

My take on that would be that if the business takes off it'll quickly justify the bigger machine in its own right. That doesn't mean the smaller machine is redundant, far from it; anyone here that runs a machine shop (Jazz, JohnS, etc) knows that having more than one machine allows for multiple jobs at once...or backup in an emergency.

At a 100/week, thats 20 a day... I dont know the complexity but I'm guessing 15min or so per job, thats 5 hours run time a day. That's not insubstantial and you need to consider that in the size/performance of the machine. If you weren't CNCing them what's your plan B?

kemo_2002
28-08-2012, 06:26 PM
My take on that would be that if the business takes off it'll quickly justify the bigger machine in its own right. That doesn't mean the smaller machine is redundant, far from it; anyone here that runs a machine shop (Jazz, JohnS, etc) knows that having more than one machine allows for multiple jobs at once...or backup in an emergency.

At a 100/week, thats 20 a day... I dont know the complexity but I'm guessing 15min or so per job, thats 5 hours run time a day. That's not insubstantial and you need to consider that in the size/performance of the machine. If you weren't CNCing them what's your plan B?

100 a week may be slightly ambitious! i think a more realistic figure would be 5-10 a day. my plan B is to buy in the letter, which i really dont want to do, so its plan A or plan A really, its something i have wanted from the beginiging but have been fortunate to get up and running and accumalatea nice profit by getting them 'for free' only i am restricted to how many as he is meant to be working!

at the moment i am using the letters for keepsake boxes, so every box is one letter, i am currently doing 10-20 boxes a week, but with a cnc i would do more letters as i could expand with the things i could do, eg decroative letters, wooden bunting, ect ect....i hope this makes sense :)

irving2008
28-08-2012, 06:39 PM
Perfect sense... and a good application of CNC. Sounds like you have a good fledgling (or maybe even more so) business there and doing OK seemingly even with the recession. Clearly with more capability and therefore more product options at a lower works cost (time = money), a CNC machine of some description would make good sense and a smallish one to start would seem to fit the bill. I know others will always say buy the biggest you can because you don't want to limit yourself, and I tend to agree, but one has to cut one's cloth so to speak. My advice would be to look at how many letters you would buy in and what the delta between what it would cost you to make them (not forgetting your time is a cost) over the cost of buying in... what would the ROI on a 1500 investment be assuming that the equiment has a 4y life span and a resale asset value.

kemo_2002
28-08-2012, 07:15 PM
wow -im not really sure about that, each letters costs roughly 1 to buy, its hard as im not sure what else and how much i will be selling when i expand, i had thought about selling blanks too, as i know that i have purchased them in the past so other people may also, i know a lot already do on here, but at the moment in only sell on ebay andthere are less sellers on there.

My main problem is I dont know what im looking for, i know what i want it to do, but not exactly the machine i need, and also the programme, my other half uses a program called 'xilog' but says its quite comfusing (and in italian!) and he thinks i would benefit in something easier to use, but something i can change fonts and size ect...

irving2008
28-08-2012, 09:11 PM
ok, simple trial ROI test... I know nothing about your business or your profit margins etc so this is just some crude back of envelope working... but it serves to show that the CNC is a viable profit generator IMHO...

Each letter costs 1, and 100/week so outlay = 100/week

MDF board from B&Q (and its a lot cheaper from ebay bought in bulk) 9mm = 13.78, 12mm = 16.48 and you get at least 98 letters a board (more if you used full sheets) Cutting is 10/sheet (50p/cut)

Therefore the letters for the week cost, worst case 26.48 + collection from supplier, say 35/week

Leaving out electricity costs for running router, there's only your time for collection and set up. Lets say initially you don't cost your time, then the savings to be made are crudely 65/week so a 1000 router will pay for itself in 16 weeks and still have a value of 700 at the end of year 1 (3yr straight depreciation).

Now lets allow for your time, say and hour to collect and 2min per letter to set up = 4.5hours @ 20/hour = 90/week.
If the router cost 1000 to buy, paid off over a year @12% interest (on a CC) then its costing about 100/month, or 25/week.
Therefore the CNC route is now costing 150/week... or 50 more than buying in the letters. Seemingly a negative ROI, but you then have to factor in the opportunity value of what else you could be doing with it.

If you can use it to generate other sources of income, selling blanks or other goods made with it then you only have to clear another 50/week for it to start paying for itself.

To me that sounds perfectly doable...

kemo_2002
28-08-2012, 09:40 PM
ok, simple trial ROI test... I know nothing about your business or your profit margins etc so this is just some crude back of envelope working... but it serves to show that the CNC is a viable profit generator IMHO...

Each letter costs 1, and 100/week so outlay = 100/week

MDF board from B&Q (and its a lot cheaper from ebay bought in bulk) 9mm = 13.78, 12mm = 16.48 and you get at least 98 letters a board (more if you used full sheets) Cutting is 10/sheet (50p/cut)

Therefore the letters for the week cost, worst case 26.48 + collection from supplier, say 35/week

Leaving out electricity costs for running router, there's only your time for collection and set up. Lets say initially you don't cost your time, then the savings to be made are crudely 65/week so a 1000 router will pay for itself in 16 weeks and still have a value of 700 at the end of year 1 (3yr straight depreciation).

Now lets allow for your time, say and hour to collect and 2min per letter to set up = 4.5hours @ 20/hour = 90/week.
If the router cost 1000 to buy, paid off over a year @12% interest (on a CC) then its costing about 100/month, or 25/week.
Therefore the CNC route is now costing 150/week... or 50 more than buying in the letters. Seemingly a negative ROI, but you then have to factor in the opportunity value of what else you could be doing with it.

If you can use it to generate other sources of income, selling blanks or other goods made with it then you only have to clear another 50/week for it to start paying for itself.

To me that sounds perfectly doable...

Thankyou! that makes it alot more clearer, i do think it will be beneficial to my business, now i just need to think what to get, i know the best value for money is to build, but niether of us have any expierience in machinery building, like i say, he works on one, but not a clue how to build one! then it comes down to buying one, and a UK is going ot cost a packet, not 1K like you based your figures on :(

irving2008
28-08-2012, 10:35 PM
Have to keep an eye out on eBay... there are several new for under 1000 with a 200 x 300mm work area (3020T) or 275 x 385 (3040T), but it might still be worth shelling out for an A3 or A2 size unit.

Often a used one comes up, like this 3020T, just listed: CNC ROUTER / MILLING MACHINE / ENGRAVER | eBay (http://www.ebay.co.uk/itm/CNC-ROUTER-MILLING-MACHINE-ENGRAVER-/170902579763?pt=LH_DefaultDomain_3&hash=item27ca966a33)

kemo_2002
28-08-2012, 10:41 PM
Thankyou, i would definately shell out the extra for a bigger workspace, are there any pointers you could give me in reccomending what i should be looking for in a good CNC (one that will do the jobs i want it to anyway)
out of interest would something like that be aapable of doing say 100-200 letters a week? and also ability to do freestanding letters?

Thanks for your help!

irving2008
29-08-2012, 12:00 AM
I'm sure Jazz and others will leap in with their thoughts shortly... but here's mine.

The key things to look for in a CNC machine are (in no particular order)

Work area - is it big enough for what you need? Obviously a 200 x 300mm machine will cut out 150mm high letters, but a machine with a 600 x 1200 bed will take a 1/4 sheet of mdf and can cut 15 or so in one pass, saving setup time, as well as handling those bigger jobs. So you need to take a view on what would be the ideal size for your set up - not forgetting room for the machine, a 600 x 1200 machine needs a working footprint of 1800 x 2000 or so.

Work height - tricky one this. Ideally the minimum you can get away with because a large work height (z-axis) means the machine is less rigid unless constructed of heavier duty materials, and therefore in turn is heavier and more costly to get the same speed. So consider what you might want to cut... just MDF? 30mm work height is more than enough. putting some decor on the base of a wooden box? you might need 100mm or so depending how big the box. Its areas like this that you might, in time, consider 2 machines.. a large one with low work height for sheet work and a smaller one with a larger work height for those more complex but physically bulky jobs.

Rigidity - cutting MDF is easy... but what else might you want to cut? hardwoods, light metals (aluminium, copper, ?). The harder the material the more rigid and physically heavy the machine needs to be.

Traverse speeds - there is a trade off between cutting speed, spindle (cutter) power and rapids speed (the speed the machine can traverse when not cutting). Faster = more expensive. If your letter is a simple A 150mm high and 100mm wide it has a cutting path of roughly 700mm . So a machine capable of 1000mm/min cutting speed will take around 5 minutes or so to cut that out depending on the number of passes (e.g. 5 passes @ 2mm depth). That may be fast enough, but add some decoration to the surface and some twiddly font bits and suddenly you could be looking at 20min to cut it. Is that fast enough? Only you can say. Obviously the bigger the machine the faster you want it to go, but bigger often means slower unless you throw money at it. So try and assess what sort of speed you need.

Spindle speed and power - this determines how big a cutter you can use and how fast it cuts. A high traverse speed needs a powerful and fast spindle motor to avoid burning/scorching the wood due to rubbing rather than cutting. Many larger MDF cutting machines use conventional wood routers but recently the trend is to lowish cost variable speed water cooled spindles using high performance motors derived from the very high power/low weight motors designed for model aircraft and the like. They have the advantage of being (relatively) quiet and have high-duty cycles (how long they can run for before needing to be left to cool down), some exceeding cutting times of 20hours or so. Low end machines will use spindles based on hobby pencil cutter tools like Dremel or Kress; these are quite effective but very noisy and wont stand much abuse.

Quality of components - cheap routers use unsupported rails and trapezoidal screws; speed and rigidity suffer. that doesnt mean they cant be used, but you need to know the limitations of the machine, generally cheaper machines will do the job but at the expense of needing much lighter cuts at slower speeds... A quality machine will have ballscrews and supported rails.


Once you have the machine, you need a PC to drive it (probably not your main work PC else you'll get nothing else done). CNC needs a dedicated PC but it only needs a relatively low spec machine. Pick up a cheap Pentium 4 circa 2007/8 running windows XP on eBay for 50 and it'll easily do the job.

Then you need the software. There are three stages - design, tool path generation and machine control. Theres lots of free software that will do the job. In the design software you lay out your shape and turn it into a set of vectors, usually in some standard drawing file format such as DXF or DWG files. The toolpath generation software works out the coordinates/paths that the cutter needs to traverse and their sequence, allowing for the size of the cutter, machine speed, depth of cut, etc. It works out when to raise the cutter and put it down again to cut out internal bits. It generates a G-code file - a sequence of machine commands of speed and direction. Finally the machine control software takes the G-code file and drives the machine to perform the cut. It is generally the last bit that runs on the dedicated PC.

I dont know about font generation but I'm sure someone will... I guess its a case of having the fonts in an appropriate vector format so they can be imported into whatever design software you use so they can be manipulated and positioned.

Hope that helps a bit. Any more questions just ask, no question is too stupid.

Fivetide
29-08-2012, 12:30 AM
I saw this tonight on ebay , you may get a bargain but it looks like the kind of think for doing the mdf .. wood letters
CNC ROUTER / MILLING MACHINE / ENGRAVER | eBay (http://www.ebay.co.uk/itm/CNC-ROUTER-MILLING-MACHINE-ENGRAVER-/170902579763?pt=LH_DefaultDomain_3&hash=item27ca966a33)

6692

6693

Hope it helps sorry if I'm way off :)

Jonathan
29-08-2012, 01:53 AM
I think you should seriously consider a machine big enough to cut a reasonable number of letters from one sheet since, unless cutting letters from identically sized pieces is the sole purpose of the machine (in which case you use a jig to speed up the process), you could well find set-up time to be greater than the time taken to actually cut the part.



6693

Hope it helps sorry if I'm way off :)

No apostrophe :(

kemo_2002
29-08-2012, 08:34 AM
Work area - is it big enough for what you need? a machine with a 600 x 1200

Rigidity - cutting MDF is easy... but what else might you want to cut?

So a machine capable of 1000mm/min cutting speed will take around 5 minutes or so to cut that out depending on the number of passes (e.g. 5 passes @ 2mm depth). That may be fast enough, but add some decoration to the surface and some twiddly font bits and suddenly you could be looking at 20min to cut it. Is that fast enough?


Thankyou for all your replies, in order to answer a few point, i would definately want the bigger work space doing one letter a time would take a long time i fear.

i will mainly be cutting MDF wood but possibly up to 18" for free stading letters, obviosusly if i have a machine capable of other woods i would look to use them, bt this is not a top priority on things i would like.

then it comes to cutting speed, up to 20 mins per letter is quite long, i would obviously like something quicker if i can, the picture than was put for an item on ebay looks like it would do a good job for me, only the working area is very small, this may have to be my compromise to stop having to pay silly money.

with all that taken into account, roughly how much am i looking at needing to save up, my business turnover is around 5k net profit per year (it would certainly be more if i wasnt restrictied im sure) i could fork out 3-4 grand at hthe end of hte tax year if i had to, to get something i want but then i have to look at how long it would take for me to recoup that money...a long time i would think

Thanks again all :)

irving2008
29-08-2012, 10:57 AM
my business turnover is around 5k net profit per year (it would certainly be more if i wasnt restrictied im sure)

Couple of thoughts..

1. you're looking at this from the wrong angle... 5k net profit means you are paying ~1.25k pa in tax? Any capital expenditure you make in the tax year is deductable against taxable income (see here (http://www.businesslink.gov.uk/bdotg/action/detail?itemId=1086384469&r.i=1086384138&r.l1=1073858808&r.l2=1086692188&r.l3=1086445219&r.l4=1086383994&r.s=sc&r.t=RESOURCES&type=RESOURCES)for more info, it differ depending on whether you are a sole trader, partnership or a limited company) so at least some if not all of the cost of the equipment can be offset against tax. If you are careful you can do it across two tax years as well...

2. Investing 25% of your income into extending the business isnt unreasonable, so putting 1k+ a year back into the business to increase its turnover and profitability is sound planning

On that basis (and you need to do the numbers more appropriately for your actual situation - or get your accountant to) a 4k+ spend seems perfectly reasonable.... and the ROI is probably better than you think...

John S
30-08-2012, 12:40 AM
If you are using cut pieces of wood as opposed to say 1/2 sheets [ read expensive machine ] think about nesting the letters seriously.
I don't mean nesting as in doing J's as spoons but see about getting thinner letters to go at the side of wide sloping letters.

Something like a J upside down, then an A followed by a A upside down and finally another J or L right way up will use virtually the same amount of wood as the two A's.

You also want a CAM program that can leave tabs like Vcarve so all the letters stay in the parent material until broken out and the tabs sanded off. This way it stops damage to the letters and tooling.