Material Handling Training

1
Material Handling Training

• Frontline crew of fast changeovers

2
Overview

• Introduction to resin bases
• NASCAR Anticipation, not reaction
• Material Characteristics
• Loader set-up and maintenance
• Dryer set-up/ care
• Using Schedule to plan your shift
• Filters cleaning schedule, procedures and
  importance
• Extrusion process and troubleshooting
• Glass transition and overdrying
• Dos and Donts
• Using Throughput to reduce waste of motion
• Color Changes 3 to 7 minutes
• Optimized cleaning based on material change
• Colorants Use and troubleshooting
• Purging Procedures and approaches
• Material temperatures
• Drying temperatures
• Dryer mechanical
• Loading calibration

3
Section I Resin Bases
4
Thermoplastic Materials

• Amorphous
• Large melt window
• Melt occurs as temperature rises
• No glass transition point..acts the same as
  butter softening
• Molecular chains similar to spaghetti

• Crystalline
• Melt occurs at glass transition point
• Narrower melt window
• Molecular chains are flake-like
• More susceptible to overpacking defects (voids,
  cracking, stress)

5
Materials By Type

• Amorphous
• Nylon
• ABS
• Polystyrene
• Acetal
• Polypropylene
• Santoprene
• Poly Vinyl Chloride (PVC)
• PC/ ABS

• Crystalline
• Polycarbonates (PC)
• Acrylics

6
Glass Transition

• Glass Transition is the actual temperature that
  crystalline materials change from a solid state
  to a melted state
• It refers to the properties of crystalline
  materials being similar to melting silica in
  glass production
• Material manufacturers define this on the MSDS
• The range from the transition to the point that
  material degradation occurs is considered a
  crystallines melt window

7
Melt Window

• A materials melt window is the desired range of
  temperature that a material is processed.
• Mean melt temperature refers to the center of the
  highest and lowest processing temperatures
• The manufacturers material safety data sheet
  (MSDS) defines the high and low temperatures for
  their materials

8
Hydroscopic Material moisture

• Hydro refers to water
• Materials have different levels of
  hydroscopicity..meaning some materials are more
  prone to drawing moisture into the pellet
• Nylon is an example of a material that is
  extremely hydroscopic..it takes on water quickly
  and easily.
• Polypropylene is an example of a material that
  does not absorb water well

9
Hydroscopic Material moisture

• Crystalline materials take the longest to remove
  moisture..the pellets are more dense and
  compacted.. Thus longer drying time is necessary
  to prepare the material for processing.
• Material additives can increase a materials
  potential for drawing moisture. Polypropylene has
  low hydroscopic properties..but when talc is
  added, it can become hydroscopic.

10
Hydroscopic Materials Examples

• Hydroscopic
• Nylon
• PC/ABS
• ABS
• Polycarb
• PEEK

• Non-Hydroscopic
• Acetal
• Polystyrene
• Polypropylene
• PVC

11
Specific Gravity

• Specific Gravity refers to a materials density
  and weight
• A material s density depends on how well its
  molecular chains align
• Materials that have tightly aligned chains have
  higher densities
• Materials that have loosely aligned chains have
  decreased densities
• High density materials weigh more than low
  density materials

12
Specific Gravity

• All materials are compared to styrene, which is
  considered to be the mean (or middle) of material
  densities. It has a value of zero.
• Materials that have negative values have lower
  specific gravities than styrene
• Materials having positive values are considered
  higher specific gravities.

13
Do I Need To Know This???
YES!
14
How it Relates to YOU

• Specific gravity is why materials have different
  weights. Dense materials weigh more, low-density
  materials weigh less
• A barrel filled with Polycarb will weigh a lot
  more than a barrel of polypro because of the
  difference in their densities

15
How it Relates to YOU

• Knowing how to look at the area of a hopper and
  calculating how much material is in it helps to
  reduce waste of motion
• It also helps you to calculate how much material
  you need to complete an order and prep for a
  changeover
• Which leads us to the next topic

Throughput
16
Throughput

• Throughput is a method of calculating the amount
  of material used
• This can be calculated per cycle, per minute, per
  hour or per shift
• The formula for calculating throughput is
• (shot weight) x (cycle time)
• ( cycle throughput)

17
How to Use This Formula
18
Working Example Throughput

• Using a nylon handle, you estimate that the shot
  weighs ¼ of a pound (.25)
• The press is running at a 30 second cycle. This
  is 2 shots per minute.
• 2 (shots per minute) x .25(Shot weight) ½ pound
  per minute (.50)
• It takes 2 minutes to use one full pound of
  material

19
Working Example Throughput

• 60 minutes(1 hour) divided by 2(which is how
  many minutes it takes to use 1 pound) 30 pounds
  per hour
• If the press is going to run your whole shift,
  you can use this number to figure out how many
  pounds you need at the press
• 30 x 10 (which covers 8 hours on your shift and 2
  hours of the next shift)300 pounds
• If the hopper holds 500 pounds, then there would
  be plenty of material for the whole shift
• If the hopper holds 200 pounds, you would need a
  full hopper and another 100 for 10 hours run time
• Its always better to have extra, rather than too
  little. Pad the number by adding an extra 50-100
  pounds. Thus, 300 50 extra is 350 total pounds
  needed.

20
BUT WAIT..

• Can we use this formula to prepare for material
  changeovers?

YES WE CAN!
21
Changeover Preparation

• Based on the same partswe know we use 30 pounds
  per hour
• Say that we look at the KanBan and need 480 more
  parts
• We check the mold and every cycle we make 2 parts
• 2(parts) x 2 (cycles per minute, based on a 30
  sec cycle)4 parts per minute
• 4(PPM) x 60 (minutes in an hour) 240 parts in an
  hour
• 480 (parts needed) divided by 240 (PPH) 2 hours
  runtime left

22
Changeover Preparation

• We need enough material to run two hours,
  correct?
• We already determined we need 30 pounds per hour
• 2 (hours left) x 30 (pounds per hour)60 pounds
  needed
• We pad the number to compensate for scrap
  60(needed) 40(to be safe) 100 pounds

23
Changeover Preparation

• Now we know we need 100 pounds..here is how we
  use the information
• We look at the bin mounted to the press.. We
  calculate it holds 30 pounds. This tells us that
  we have 1 hour of material in the bin
• We know that we expect to run for two more hours.
  100 (pounds needed) -30 (in the bin 70 pounds
• There is a standard rule that material will not
  draw moisture for 1 hour

24
Changeover Preparation

• Based on the 1 hour moisture rule, we can
  drain the hopper 1 hour prior to the change.
• The material drained is dry we place 50 pounds
  in a barrel, and continue loading the press but
  from the barrel instead of the hopper.
• NOTE High scrap affects the amount of material
  you need prior to changeover
• NOTE 2 A press that is not running steady
  affects your time as well

25
Best Practice?

• How do I know when prepping my changeover is
  possible?

26
Assessing a Changeover

• Check the operators PIMIS sheet to determine if
  there has been a lot of downtime.Excessive
  downtime makes the 1 hour moisture rule null
  and void.
• Ask the operator if they have had a lot of scrap.
  Excessive scrap means longer run times and
  increased material usage!

27
Material Changeover vs. NASCAR

• Material Changeover

• NASCAR

28
Material Changeover

• Material changeover refers to a mold or color
  change
• The primary factors of changeover are hoppers,
  material, grinders, drying, colorant and press
  mounted bins
• NASCAR and material changeovers are unique in
  tasks but similar in preparation! NASCAR pit
  stops can be used to develop a material handlers
  approach towards fast and effective changeover

29
The Perfect Pitstop
What factors will affect your changeover time
most?
30
Communication/ Scheduling
First of all, it is important to plan the change
according to past data as well as what is
crucial for success
31
Communication/ Scheduling
The efforts of all members must be coordinated
prior to the change.. Stray and unplanned
activities result in chaos, as well as wasted
motion. This causes poor response and weak
response times
32
COORDINATION
APPROACH Each member of the team has pre-defined
tasks as to how they need to perform the tasks of
their job. TOOLS Unneeded tools are removed
from the work area to reduce the amount of
thought associated with tool choice. Meticulous
thought into what tools are needed, and tools are
purchased based on quality and job
efficiency. PROCEDURES Job definitions are laid
out based on what steps are needed for efficient
and lean task completion. These tasks are then
analyzed for flow.. Can steps be removed? Is
there waste of motion? Can they be improved
through tools, approach, other means?
33
COORDINATION
MACHINERY The injection machine itself is our
race car.. Can we modify the machine to improve
our approach? Are there components that reduce or
add to our changeover times? TRAINING
Understanding the tools, job expectations and
equipment used are imperative to company success.
Strengths are taught, and weaknesses are
addressed for individual and team improvement by
learning and practice. R D Are there new
techniques, approaches or technologies available
to us that can improve our approach? Do we strive
to continuously improve our process? How can we
reduce our changeover times? Can we improve our
response to problems?
34
On The Track

• Keeping the press running is crucial! Running out
  of material or color is the same as an
  unscheduled pit stop.. It is
• Unplanned This creates waste of motion and poor
  response.
• Extra Work By not prestaging material, you
  increase your work load.
• Decreased Productivity
• Press down time causes
• added scrap due to
• press restarts, and increased downtime due to
  unscheduled response

35
Failure is inevitable.. The key is to define the
failure and develop solutions or countermeasures
to become successful

• What if we fail?

36
Keys to Quick Changeover

• The following are keys to fast changeover
• Anticipation Planned changes are smooth and
  require less effort.
• Tools Knowing what tools you need and having
  them ready will assure the change is quick
• Knowledge Understanding your equipment and
  procedures assure speed and accuracy