A series of non-technical questions

Bill and Rick, Thank you for taking the time to respond to my questions. I appreciate all input. Things tend be different at our plant as we do many different parts rather than a few parts at high volume. I think I'm going to end up taking the manual for the dryers away from the maintenance guys and try doing most of it myself. All of the dryers are previously used, and in some cases severely abused, so we're doing the best we can with what we've got.

Inventory is still dicey at times. We have our internal system and one I created with Word. I take every couple weeks or so and do a physical check. Sometimes I find that material that people forget to return to the system, sometimes I don't. It's just too bad that the program they use is outdated and AS/400-based instead of a Windows-based database with a GUI (Graphical User Interface).

I like Bill's sponge ball idea and am going to start looking at some Nerf products for sizes. Rick, thank you for your explanation of properly grounding the hoses. As for mixing, our esteemed maintenance team decided to put our mixer in a gated room with limited access. Over the next few months our building will be added onto and we are going to make sure that this error is corrected. We're still trying to talk them into a barrel mover/weigher.

As always, though, I still look for solutions to efficiency, be it with the material, storage, drying, or just computer/paperwork stuff.

As I end up with more questions I'll post 'em up here in a new post.

I'll try to offer some help!

1) We have some really old dessicant dryers here. How old is too old? What would be a good way of arguing for new dryers (maintenance, energy, efficiency, etc.)?
I show them that the unit is not drying the resin (dew point), and here is what the scrap is costing us. I must say that I have seen some very old driers (1970's) that run perfectly well, and others that don't (3-5 years old). Two main causes for this. 1-lack of training(replacing filter while the unit is running).2-abuse(the filter thing, running w/o filters, no pm work, running VERY dusty regrind through them). Lastly, many times I see a drier that is too small for the through put of the molding machine or produces marginal dew points; then the hopper is ran dry/low! Add low level (audible) alarms to your hoppers. You will be surprised how often they alarm!

2) What are some tried and true methods for reducing contamination?
Keep the same resin or colors in a press. Run hoppers (machine) dry, so no resin to drain. Purchase hoppers than can be broken down for cleaning/changes, and have replaceable wear components. Have enough driers to reduce the number of cleanings that must be performed. Standardize on components. It makes it easier for ALL when working on them, and spare parts.

3) What are some good storage options for previously-run material?
Small resin bins from one of the many suppliers, or trash cans with latching lids.

4) What's the best way to load a tilted, upright barrel mixer?
Barrel hand trucks and a ramp to get the trucks up and down from the platform.
Get a good used weight blender. Several would be great so you can machine mount them. You could use a vacuum loader, setting up a station that has the unit adjustable for height. Then you can use a sleeve mounted to the bottom to keep the resin as it drains from running out of the top of the barrel. By the way, don't fill barrels more than about 75% percent full. If the resin can't tumble, it won't mix very well.

5) Are Venturi air movers the only solution out there for transfering materials?
Vacuum loaders, self contained or receivers with a vacuum pump, will make you weep! With a vacuum pump, they can remove the dust/fines when conveying and help reduce your scrap. Plus, when used with a properly grounded hose, you will enjoy your job more!

6) What is a good inventory system/program for keeping track of on-hand material? Freeware is preferable. Our internal database is almost always wrong and am hoping for an easier solution to double-check it.
This is a struggle for most every company. The hardest part is the diligence required to use whatever system you have! I have seen Excel spreadsheets, with the right person setting them up, that worked great. They could even calculate how much resin, color, and boxes were needed for a given numer of parts.

7) Has anyone encountered some bend-resistant dental/wax picks for those hard-to-reach areas?
Thankfully this is not an issue. Now, I have used some picks from Snap On, available in a kit, that work great when working in molds.

8) What's been the best solutions you've seen for preventing static shock incidents?
EARTH GROUNDED MACHINES, resin handling hard lines, and grounded hoses. Now the trick with a grounded hose is this. People don't know how to use them! You must bare the ground wire, bend it inside the hose, then tighten with a hose clamp onto the wand or hopper. This MUST be done on BOTH ends. Now, you won't end up wetting yourself! Lastly, get rid of the pcv pipe and vacuum hoses you more than likely have on the machines. With the resin flowing through the hose, then the plastic pipe, 3 feet will be about 3 feet short of where you'll end up! EMT works, but hard lines for this are available everywhere now days and are smoother inside. You can use aluminum for the straight sections, then stainless for the bends. You end up with a better price, and the wear items (bends) will last longer. Best system I enver seen/worked on, had glass elbows in the highly filled resin lines (70% filled PP).

I hope this helps!Rick.

Just to clarify a few of my points:

1) Some of the dryers just don't want to dry material properly regardless of desiccant change, heater change, cleanliness, etc. Also, do your maintenance teams perform regular check on your dryers? Ours only seem to look at them when they're a total catastrophe.

2) We have labeled hoses based on resin color and try to use them exclusively but sometimes the build-up gets bad. You mentioned a sponge ball. What brand/model would you recommend?

4) Our barrel mixer sits a bit off the ground (13 inches), so we load an empty barrel on it and hand-load material, but our safety team is concerned about removing the 100+ Kg barrels after they're mixed.

5) Been trying vacuum systems as well. For example, removing 60 Kg or so left in a gaylord to be put into a barrel for space-saving. The Venturi works, but pushes a lot of air through into the barrel that sometimes material can go shooting out (quite a fountain sometimes, rather pretty) while vacuum systems I have to stop every few minutes to clean the filter or it stops working.

6) Been using Microsoft Word and making tables in there, printing out the lists each month, hand/eye-verifying, and making corrections to this list. I was just hoping that there might be something easier.

7) Seriously. I use the picks to get material out of filters, in crevasses within the dryer, the vacuum system, and most importantly, a little gap that exists on most of my dryers between the hopper and the cart in the shut-off valve area. I have to pull out material from within or else we end up with black resin during a white run. Only, some resins get stuck good in there and the picks I use bend or break after time. Sure they're only a couple bucks apiece, but I have to drive for 2 hours to a little shop to get them.

8) Unfortunately we don't have very good grounding spots at our presses. We have a couple brass rods that I end up running down the side of the wand with a small alligator clip to go to the press or electrical box. Sometimes it works, sometimes not. I just managed to get in a couple of the shoe-heel straps. Hopefully that will help. Recently we had a small stack of bags near a press and it built up enough charge to throw me back about 3 feet. Felt like being kicked by a mule. As for the hoses, would you suggest exposing a length of the wire and attaching it via hose clamp to the wand and somehow to the vacuum unit on the other end?

Also, we've recently found out that the company is expanding the facilities, but after talking to our general manager it appears that we're losing about 700 sq. ft. of material storage/work space. Argh! This is why I'm looking for better storage solutions and efficiency examples.

I've also been taking the time to create Excel spreadsheets to keep track of jobs, programs for my calculator to keep track of press ending times, and data on the job runs themselves to help the engineers to improve the work instructions.

Drew Vedbraaten

Drew

Answers per your questions:

1. Desiccant dryers don't die, desiccant does. Make sure the filters are clean and the desiccant is functional.

2. Reduce cross contamination with good house keeping:
- keep everything covered
- clean out loaders and transfer equipment with a damp rag.
- clean out the hoses/tube with a damp sponge ball sucking it through the system.

3. Cover, label, keep it clean

4. Best way to load - carefully. By hand, use a bucket.

5. Venturi are the easiest to maintain. You can use the grain handling screw auger types but then tend to mash/melt the material.

6. Any freeware or purchased system depends on the discipline of the people using it. You MUST log everything in and out to maintain an accurate count. If the system is too complex, people will either ignore it or find a way to get around it.

7. Cute - see a dentist

8. The only solution to Static dissipation is Earth Grounding. For fixed equipment, drill a hole in the floor, pound in a copper rod to the damp soil. Make a direct electrical connection between the equipment and the rod. Use wire impregnated flexible hoses, with wire connections to the wands.

For portable equipment use a battery cable to ground the equipment to the nearest I-beam or metal water pipe.

There are your answers. The rest is up to you.

Bill