Questions for Wayne

1)Why American made parts?

a)‘Made in America’ part requirement is for patriotic reasons but customer has also had excellent experience with the overall quality of American made parts; they feel they last longer and are of a superior quality than oversees parts (especially gears, bearings, etc)

2)The customer designed their attempt

a)Not a wire saw but a blade saw

b)He rocked the blades (Wayne believes this was the mistake because for the material they cut rocking isn’t needed and straight plunge cutting is the way to go)

c)They weren’t able to tension the blades

d)The created a ‘package’ of 40 blades to perform the cuts but because they couldn’t tension them they could never get 40 parallel even parts

3)What is the footprint size we should try to achieve?

a)For the footprint Wayne wouldn’t give us a number for the maximum footprint size of the new machine, just smaller than the Meyer Burger

b)Ed suggested created stretch goals:

i)Max = 50% of the Meyer Burger sq. ft.

ii)Goal = 25% of the Meyer Burger sq. ft.

iii)Min = 20% of the Meyer Burger sq. ft.

c)We are also not constrained on the layout of the machine (we can make it long and skinny or a square shape and anything in between)

4)Where will the machine go in the facility?

a)Customer doesn’t have a specified spot for the new machine on the shop floor yet.

b)Overall weight of the new machine is a potential issue

c)Goal is to considerably cut the weight compared to the Meyer Burger

d)Worst case nothing heavier than the current machine

5)How is the wire indexing rate calculated or is one setting for all jobs

a)Wire indexing is an adjustable value: Meyer Burger gave customer a recommended value and that is what they use

b)But we could play around with this value

c)The operator controls how much wire goes forward and how much goes back (400 m out and 395 m back)

6)Do you want to optimize the use of the wire?

a)Customer pays $3.50 (possibly a little less than that) per km of wire

b)475 km of wire per supply spool

c)Optimization of wire isn’t super important but they would like us to scale appropriately with the changes we make

d)Wire isn’t reusable once it is on the takeup spool

7)What type of pulley does the Meyer Burger machine use?

a)The DS264 has metal pulleys with nylon (hard rubber) inserts

b)These inserts are relatively cheap

c)They replace the inserts on the DS264 about every other month

d)There are 2 different sizes of pulley inserts on the DS264

8)What is the power reduction that you are looking for?

a)For our machine Wayne would like to cut everything at least in half (power consumption, guide rollers, machine footprint, etc.) but Wayne doesn’t want to cut the size of the spool in half

9)How long do the spools last and do you want us to scale them down accordingly with the machine?

a)Right now the spools last them about 3 months, so we’d want to keep that the same as if we scale the spools down, then they should still last the same time

b)Scale down the spool size and the amount of wire on the spools to meet their routine maintenance period

c)

10)What is the maximum ingot size?

a)Max ingot size of 220mm by 220mm

11)How many cuts would you like this machine to do?

a)Number of cuts to range from 50 to 270

12)What is the diameter of the wire?

a)The wire they currently use has a diameter of .175mm

Questions for Ray

1)Is the wire indexing rate a calculated value or is one setting for all jobs?

a)Can be set between 500m and 300m

b)Ability to change is important

c)Is 400m forward 395m back / was 500m forward 495m back (Ray just found a value he liked)

d)*this could be an opportunity for good technical analysis to develop a function of workpiece width or volume to give index rate

2)How much does the wire bounce up and down as it travels through the machine?

a)No visible bounce?

3)What motor is being used for spool movement? (see it)

a)Pay-off spool model nameplate

i)

b)Take up spool motor nameplate

i)

c)Motor for dancer

i)

d)Motor for spooling pulley

i)

4)What is the timing of the wire movement?

a)Programed in, decent depth (183mm for this job)

b)Broken into 12 step process, input % of max descent rate (0.2 mm/min) drops at most to ~80% (0.14 mm/min)

i)Based on maintaining a 2mm bow (visually determined)

ii)*opportunity to incorporate a bow sensor?

c)Always runs wire at 12 m/s at 100% feed rate

d)Wire speed and feed rate are most important variable when it comes to cut quality

5)What is the main cause of down time?

a)Wire breaks take a long time to fix

b)Set-up (spooling) takes really long time

i)2 people, 20 ft of wire unspooled and set on the floor, washer tied to the end of the wire and tossed back and forth

6)What type of materials do you use? Do you know the density?

a)Pyrex, quartz, BK7s, GFS, No optical (harder materials)

7)What is the maximum weight of most work pieces that you cut?

a)150-250 lbs (guessed)

8)How far does the fixture need to be from the wires so that wires can safely be changed?

a)Currently only about 3 inches from wire to workpiece when backed out completely

b)Without a work piece about 1.5 – 2 ft

General Notes:

  • Dancer motor measures the tension (24N) that is called out on the control panel (springs or strain gauges they think)
  • Thin cut jobs often have at least one piece break away and fall onto the wire, this breaks the wire often
  • * opportunity to design tray to go under workpiece but above bottom wires to catch falling pieces (mesh to let slurry through)
  • Lift cart is used to mount the workpiece
  • Ray uses zip ties to hold dancer in upright position during set-up
  • Dancer moves about +/- 0.5 in at steady state conditions, moves about +/- 2 or 3 in during direction reversal process
  • Machine alarms and stops if dancer is too far off from vertical
  • While the machine can run at a max wire speed of 15 m/s, Ray usually runs it at 12 m/s
  • Ray usually only configures the feed distance before starting? (although other parameters are configurable)
  • Machine calculates most variables at runtime
  • Should allow user-controlled cut speed
  • Motor drives in cabinet next to PLC
  • Wires coming out ~ 1” diameter
  • Manufactured by Siemens
  • 8-segment displays with some programmable number - not sure what it correlates to
  • Fixed acceleration of 2 m/s^2
  • Machine displays prompts for faults - i.e. dirty filter, wire break
  • 600 grit slurry used
  • Tension measured with dancer pulleys & springs (usually ~25N) and 10-12N in running mode
  • There is slurry over everything!
  • The wire just wraps straight around the spools. There is no fancy wrap pattern.
  • The tension of the wire wrapping around the supply spool stretches out the spool lengthwise.
  • The spooling pulley is synchronized with the rotation of the spool.
  • The tensioning pulley compensates the most during acceleration and deceleration.
  • The guide rollers are set up by tying a washer to the wire and throwing it across the machine.
  • The wire rubs against the sides of the spool when spooling.
  • Tension while running was 24.93-25.12
  • Spool of new wire weighs 197.733 pounds.
  • Wire from Bekaert Corporation.