MYCNCUK

New Member: About to build CNC miller, need design critique please

JW149 — Thu, 09 Feb 2012 19:25:52 GMT

Having watched Yutube and other sites, I too want my own CNC router/mill
I have created a Sketchup static model for experienced members to comment on before I buy materials.
I have omitted occassional plates so you can see my design better
I have a worktop space 450mm x 350mm max and watch machining area 200x200 or larger
I want to machine steels and brass for vintage motorcycle parts
I was proposing to use 10mm mild steel plate and 500+ oz-inch motors
Any experienced CNC hand who is in UK West Midlands who is prepared to mentor me ?
I hope I have attached several JPG of my proposed design.
Do I need to protect rails from suds and swarf?

Attached Thumbnails

RFQ: Looking For Machinists For Work Abroad

TheGrab — Thu, 09 Feb 2012 13:21:05 GMT

I am looking for workers for jobs in Cape Town START in March.

Working length: 2-6 Months

Qualifications:
You should have been in the business for at least 5-10 years and knows various machines (Example: Ponsse), you know mechanics, hydraulics and you can work on your own.

We also have an apprentice position available.

Contact:
Do you find this interesting, then contact me by email.

Mats.Ruontti @ Seaway-Offshore.Com

or by phone: 0044 74 12 74 66 74

BUILD LOG: A3 Router Build

GTJim — Thu, 09 Feb 2012 11:08:44 GMT

Hello, I am hoping that with the input of the members of this forum that I will be able to develop a design of a smallish router that is functional and reasonably simple to construct.My original goal was for a working area of 1300mmx1300mm, but for this machine it has been scaled down to a working area slightly larger than A3.This will be a fixed gantry 3 axis cnc, made mainly of steel with the exceptions of the Y axis extrusion and table.I hope that we can not only use this thread to discuss the design but also the methods of construction as I wish to learn how you would approach some of the problems I stumble across.I want this to be able to machine aluminium and wood so it needs to be rigid. I have already made a start on the side plates which are 12mm steel and very heavy (maybe a bit over the top).Here are a couple of sketches to start with.

Attached Thumbnails

How do i make this in cambam?

motoxy — Wed, 08 Feb 2012 20:03:35 GMT

I know that as soon as some one tells me I will say DOH!. What are the steps to take in cambam to produce this flange. I cannot see how to m/c away the material for the flange and leave the bosses. I realise that the panic is setting in as this could be a sign of stupid questions to come.

btw build news soon.

Bruce

I am using the free one at the moment, trying to preserve whats left of my 40 tries.

Attached Thumbnails

2.2 kw spindle problemo

chip — Wed, 08 Feb 2012 17:43:51 GMT

hello folks
ive run into my first major problem since building my router and that is the spindle has packed up and is tripping the house.
im no sparkie and wouldnt know how to run a multi meter if i owned one,

yesterday it was working fine although i did have a mishap when i lowered the spindle in its mount and didnt anticipate the cooling hoses would be too short so when z did its thing mid job they popped off pissing water every where.
i shut it down dried everything off and it worked fine,today i switched everything on and the house tripped

ive disconnected the power lead that fixes to the top of spindle. everything powers up including the inverter so the problem is either the lead between spindle and inverter or the spindle,ive no way of knowing which so my process of elimination will have to be to buy some more cable to rule that out.

but if its the spindle...,has anyone had the same problem? it seems odd to me as its not like it packed up while in use and it shut down as normal yesterday.:question:

Profile Cutting Options BobCAD CAM

aldepoalo — Wed, 08 Feb 2012 16:54:26 GMT

Cutting Profiles with BobCAD-CAM

Profile cutting is so common almost any 2D part you machine requires this type of tool path. From finishing the wall of a pocket to cutting around the outside shape of a part, profiling is essential.
We offer 3 types of profile options that accommodate for different profiling needs. These options can be found under patterns of the Mill 2 Axis Wizard

Standard:
Our standard profile cuttings allow for a rough and finish tool, stock for finish, lead in / out options and step down in z. This is the most common profile cutting tool path.
Watch a video to learn more: http://screencast.com/t/uaoSCEa1e

Contour Ramping:
This option allows you to ramp the tool around any profile. Common uses are for helical milling & slot milling. You control the angle of cut or a step down distance.
Watch a video to learn more:http://screencast.com/t/PB7txTXU7RL

Side Roughing:
Allow you to walk the tool in to a profile. Works best where you have more stock to cut then the cutter can take on a single pass.
Watch a video to learn more: http://screencast.com/t/4TNtJHmvWXW

With all profile cutting features you have compensation options, Allowing BobCAD to offset for the cutter, or to call cutter comp (G41 G42). These compensation options allow for wear comp, cutter comp, and center line cutting.

Using our profile tool path you can cut slots, shoulders, letters, holes, filets, t slots, dove tails, form shapes and other common every day 2D milling features.

If you have any questions please let me know.

Al DePoalo
BobCAM Team Leader

New Member: Good aft one and all...

Swarf — Wed, 08 Feb 2012 12:26:45 GMT

Hi there,new user to the forum here. Been running CNC's for about 15 years now,on the shop floor,80% self taught. No degrees or fancy bits of paper!! Learnt my toolmaking trade on the manuals prior to that. stumbled across this place looking for info on 4th axis setups,so there may be some questions to follow.....:naughty:
Biker born and bred as well,and I like beer. Think thats about it.....

Cheers all!

New Member: Sanyo Seiki

SanyoSeiki — Wed, 08 Feb 2012 07:33:32 GMT

Hello! I'm Sanyo Seiki, a new member of this forum. Nice to meet you all! :D

ITEM WANTED: Small Milling machine

pmcb1011 — Tue, 07 Feb 2012 23:02:48 GMT

Hi Folks
Looking for a small milling machine.
Cheers
Patrick

Z axis error woes

HankMcSpank — Mon, 06 Feb 2012 19:50:03 GMT

I'm worn out here...& ma brain is well fogged, so thought I'd throw this one open to the 'MYCNCUK Massive'!

Basically, I've got Z errors creeping in ....but I don't know where they are creeping in from!

The CNC software I use - CNC-USB has a way of 'auto Z probing' & storing the points, so what I did was leveled my bed (thanks for the endmill Jonathan!) then mounted some copper board on it - I'm pretty sure the board is flat (both because I levelled the bed, but after mounting the copper, I also did a shallow test cut from Y0->Y10 & it was perfect.

So I then then did auto Z probing at 0.2mm spacing along the Y0->Y10 line ...by the end of the 10mm probing the error recorded between 1st & last probe was 0.3875mm!! (see the list below.....that'll be the last Z probe recorded (3.30) minus the first probe recorded (2.92125)) ...this is a massive amount of difference over such a short distance of 10mm ...and like I say, in parallel with this 'probed line' I'd already done a shallow test cut & the cut was perfect (in other words the bed is very level along this 10mm line)

I am literally tearing my hair out here......the CNC machine I bought touts itself on repeatability (http://www.youtube.com/watch?v=6HZnKCrpCkI ...2m25s) ...so it might not be my machine (or maybe they just lie!) - it may be my stepper board? (an easy CNC 3 axis)...I'm just a bit puzzled where to start & if there's any diagnostic/test anyone can think of it'd be most welcome!

Here are the Z probe points along the 10mm line Y0->Y10 (I chose 0.2mm spacing to ensure there were a lot of Z moves up/down/up/down etc), every line introduces a little bit of cumulative error by the looks of it....

X0.00000 Y0.00000 Z-2.92125
X0.00000 Y0.20250 Z-2.91750
X0.00000 Y0.40500 Z-2.92875
X0.00000 Y0.60750 Z-2.93625
X0.00000 Y0.81000 Z-2.94375
X0.00000 Y1.01250 Z-2.95125
X0.00000 Y1.21500 Z-2.95875
X0.00000 Y1.41750 Z-2.96625
X0.00000 Y1.62000 Z-2.97375
X0.00000 Y1.82250 Z-2.98125
X0.00000 Y2.02501 Z-2.98875
X0.00000 Y2.22751 Z-3.00000
X0.00000 Y2.43001 Z-3.00375
X0.00000 Y2.63251 Z-3.01500
X0.00000 Y2.83501 Z-3.02250
X0.00000 Y3.03751 Z-3.03000
X0.00000 Y3.24001 Z-3.03750
X0.00000 Y3.44251 Z-3.04500
X0.00000 Y3.64501 Z-3.05250
X0.00000 Y3.84751 Z-3.06000
X0.00000 Y4.05001 Z-3.07125
X0.00000 Y4.25251 Z-3.07875
X0.00000 Y4.45501 Z-3.08625
X0.00000 Y4.65751 Z-3.09375
X0.00000 Y4.86001 Z-3.10125
X0.00000 Y5.06251 Z-3.10875
X0.00000 Y5.26501 Z-3.12000
X0.00000 Y5.46751 Z-3.12375
X0.00000 Y5.67001 Z-3.13500
X0.00000 Y5.87252 Z-3.13875
X0.00000 Y6.07502 Z-3.14625
X0.00000 Y6.27752 Z-3.15750
X0.00000 Y6.48002 Z-3.16500
X0.00000 Y6.68252 Z-3.17250
X0.00000 Y6.88502 Z-3.18000
X0.00000 Y7.08752 Z-3.18750
X0.00000 Y7.29002 Z-3.19500
X0.00000 Y7.49252 Z-3.20250
X0.00000 Y7.69502 Z-3.21000
X0.00000 Y7.89752 Z-3.21750
X0.00000 Y8.10002 Z-3.22125
X0.00000 Y8.30252 Z-3.22875
X0.00000 Y8.50502 Z-3.24000
X0.00000 Y8.70752 Z-3.24750
X0.00000 Y8.91002 Z-3.25500
X0.00000 Y9.11252 Z-3.26250
X0.00000 Y9.31502 Z-3.27000
X0.00000 Y9.51752 Z-3.27750
X0.00000 Y9.72002 Z-3.28500
X0.00000 Y9.92253 Z-3.29250
X0.00000 Y10.12503 Z-3.30000

New Member: Hello everyone. Total newbie here. Where do I begin?

DarkWalkJRB — Mon, 06 Feb 2012 17:04:40 GMT

Hi All,

Complete and total newbie here. I'm looking to get a mill and lathe so that I can make bits 'n pieces for my hobbies, Paintball and Tamiya RCs. I'd been thinking of getting these bits of machinery for years but I've only decided on actually pushing myself forward on it this year, which is all well and good, but I have no idea where to start.

So where do I begin?

I guess I should start with giving as much info as I can...

1) What am I planning to do?
As I'd mentioned above I'm into Paintball and Tamiya RC's so I'd be making or modifying parts for those two hobbies. I'm also pretty sure that a friend of mine will ask me to help him make lightsaber hilts & parts once I get going on a lathe. I don't have any plans to do anything large scale (like making hundreds of parts for selling). I only want to do hobby level parts, just small bits for my hobbies (or parts for my friends & families hobbies).

2) What materials would I be working in?
Most of what I'd modify is metal of some sort (usually aluminium but titanium, brass and steel are also used). Some smaller parts are made of plastic (delrin, nylatron, polycarbonate & acetate). I'd also like to do a few bits in some wood (grips etc.). That being said I'd mainly be working with T6061 aluminium should I actually fabricate something myself.

3) What kind of equipment would I like?
I'd obviously like to have a CNC mill and lathe (or mini versions of) but I'd like to start off with manual versions to "get my bearings" so to speak.

4) How much space do I have for said equipment?
I don't have a lot of space so I can't get one of those machines that can take up half a warehouse. I've almost completed work on a new garage which should be big enough to hold 2 small cars so if I only put 1 car in there I can give up a third of the total internal space for a new workbench to hold the equipment. I still need to complete the wiring so I'd need to know what power requirements I'd be looking at. It'd help to keep things safe.

5) How much am I looking to spend?
Money is tight all round, I'm sure, so I'm sure you won't be surprised when I say that I can't afford the most extravagant pieces of equipment. I am employed though so I'm sure that I can save up the extra funds to get what I'd need should it currently be out of my reach. I'd learned over recent years that if you get the right tools for the job, even if there are cheaper tools that'll also do that job, then you'll get the job done easier, quicker and you'll also get the job done right first time. So how much do I want to spend? I want to spend as little as possible but nothing less than what's necessary to get the right tools for the job.

6) How big are the bits I'll be making/modifying?
I guess the longest bits I'd probably make/modify would be barrels. Single piece barrels would more than likely be about 16" max. There are 2 and 3 piece barrels that can be made up to 22" but the longest part would only be about 14" on its own. Other parts will be no more than 2-3" thick/wide depending on their purpose (usually grips or shrouds). Eventually I'd like to make other equipment like a vacuum forming machine and an injection molding machine. This would mean I'd have to make the parts for those as well as the molds (whatever those would be made of). I'll cross that bridge when I come to it.

7) How soon do I want everything?
I'm in no great rush but I have been putting this off for years. I'd like to be fully up 'n running by about May/June with at least a mill. If I have to save for longer to get the right equipment then I hope to be up 'n running with at least a mill by no later than the end of August. If I can get both a mill and a lathe by then, then that'd be great.

I think that's everything I can think of (if any of that'll help) so any advice, pointers or links to info will be appreciated. As I said, I'm a complete and total newbie, so please be gentle with me.

BTW That was a lot to read and I thank you for reading it all if you did.

HELP: Tooling board

northmeade — Mon, 06 Feb 2012 09:49:01 GMT

Hi All,
can anyone tell me where i can purchase reasonably priced tooling board in the UK.

cheers, paul

ITEM WANTED: Wanted Denford Triac CNC Mill

angusnoble — Sun, 05 Feb 2012 23:58:43 GMT

Hi, I'm looking for a Denford Triac mill in good condition for conversion or converted.
Call Angus on 01803 864606 Thanks.

Simple Solution- Drive 1" Ball Screw Shaft with NEMA-23-Size Stepper Motor Shaft

LoveLearn — Sun, 05 Feb 2012 21:14:29 GMT

I have some 18-inch long 1-inch diameter ball screw shafts with dual-path ball screw "nuts." I also have some NEMA size 23 stepper motors I'd like to use to drive these ball screw shafts. About 0.65-inch end length of these long shafts is cut to a concentric 0.75-inch diameter, apparently for insertion into a support bearing. NEMA 23 size stepper shafts seem to be either 6mm or ~0.24-inch diameter. Shaft connector blocks add unwanted length, unwanted expense, and reduce heat rejection from the motor's shaft into the driven shaft, another unwanted effect. Heat rejection from stepper motors ultimately determines their duty-cycle electrical current input limit. Colder environments and better air flows enable higher driving currents. Similarly, well thermally-connected aluminum motor mounts with lots of surface area are able to reject higher heat flow rates which enable higher motor-driving currents than comparatively thermally-isolating plastic motor mounts, which would be the opposite polar extreme. Typical steel motor mounts are thermally somewhere between the best and worst. Most motor heat rejection discussions fail to consider dumping heat through the motor's shaft, yet that's a valid but minor consideration.

I've seen motor shaft couplings which include flexible synthetic rubber links. If both shafts are not concentric, flexible links allow much longer bearing service lives. But synthetic rubber is a lousy thermal conductor. Solid steel, brass and aluminum shaft couplers generally limit thermal conduction by their limited pressure contact areas onto both shafts more than they limit thermal conduction within the coupler.

Here's my simple, minimalist plan. Bore and tap a hole 90 degrees to the long screw's axis located within the 0.75-inch diameter end section. Then bore another hole about 1-inch deep into the long screw's axis starting from the 0.75-inch diameter end. Diameter of that concentric hole will be a light press fit to accept the stepper motor's shaft, which will have two flats ground on opposite sides against which two short Allen screws will press. These Allen screws will bind the two shafts together
yet be short enough to allow a flange-type 0.75 inch internal diameter bearing to support the long ball screw shaft axially and pick up single-direction thrust loads into the bearing support frame.

This configuration will be shorter, less expensive, and provide better motor heat rejection than traditional end-to-end shaft coupling configurations.

I keep learning by reading how others have found clever ways to design systems. I don't know if this suggestion rises to that standard. But it seems like it should be considered when coupling a small diameter shaft to a much larger diameter shaft.
John

ITEM FOR SALE: dormer jobber A100 drill bits

Web Goblin — Sun, 05 Feb 2012 20:41:55 GMT

I have some boxes of drill bits up for sale. They are Dormer Jobber A100 bits. Sizes are 2mm, 2.5mm, 3.2mm and 3.5mm.
I have 2 boxes of the 2mm size. 5 boxes of the 2.5mm size and 1 box of each of the 3.2mm and 3.5mm. There are 10 drill bits per box all new and unused.

Prices are say �5 per box delivered. Payment by paypal preferred. Photo is of the 2mm drills.

Please pm me if you are interested. I will have some other sixes as well but need to sort them out first so if you need a specific size please ask.

Ian